Questions on: Miscellaneous

Ron Smith, Horticulturist, NDSU Extension Service


Q: I am just like most of your e-mailers who have a plant that won't bloom. My plant has grown twice in size since I bought it and is very green. From what I've read, I don't think mine is getting enough humidity. Our house is kept as dry as possible because we don't like it damp. We live in South Carolina, where the humidity usually is high. What should I do? Would misting be a good answer? If so, how often should we mist? (e-mail reference)

A: High humidity in stagnant air usually leads to poor-looking plants. High humidity with air circulation usually improves the situation. You can set your plant in a tray of pebbles covered with water to get the humidity near the plant higher without affecting the rest of the house. Misting with distilled water also would help, but you must be consistent.


Q: I am trying to turn a weed-infested area into a wildflower savanna. I had the dead material from last year, plus some of the topsoil, removed in May. I then tilled, hoping to cut up some of the underground runners to impede regrowth of the nettles, raspberries and poison ivy. I waited two weeks to see what would pop up. Some of each grew back, plus a lot of thistle. I sprayed Brush-B-Gon on the weeds and most are wilting. I want the poison to work through the weed roots and kill some of the runners so the weeds won't grow back as heavily. What should I do next? I've considered pulling up the wilting weeds and putting them in the trash, then retilling and spreading the wildflower seed mix. Should I till and then wait for more weeds to sprout and spray again? I know I never can get rid of all the weeds, but I'm hoping that the native wildflower and grasses will be able to compete with the unwanted weeds. When will the soil be free of chemicals? I've also thought about bringing in a load of black dirt, then spreading the wildflower seeds on fresh soil. Any advice would be great! (e-mail reference)

A: The one thing you did to make matters worse was to rototill the lot. Breaking up the rhizomes of the thistle and quackgrass is one of the best ways of propagating them! I would suggest tilling everything again to see what sprouts. Spray everything that does with Roundup. Grade and sow the wildflower seed. It will germinate this summer and be beautiful for you next year. Expect to have weeds invading the mixture, but, if you stay on top of it, the weeds won't take over. Plants, such as sow and Canada thistle, will work their way back in, but with spot spraying and hand pulling early on, it won't have a chance to establish a colony.


Q: I have question about my root-bound hoya. You said to repot if necessary. When is that? Sorry to be a nuisance, but my hoya has little roots coming out through the bottom holes of a small pot. Should I put a little more soil in the top of the pot or repot? Should I fertilize? Your advice is welcome and certainly appreciated. Thank you. (e-mail reference)

A: Go ahead and repot. Most potting soil has some trace fertilizer elements added when it is mixed together, so I would hold off on fertilizing until you see some new growth.


Q: Is it true a hoya has to be root-bound in pots to flower? The plant is old and the leaves are yellowing. It is located in central Queensland, Australia. It has long leaves, but not many. (e-mail reference)

A: One of the cardinal rules for growing hoya plants is to not repot until it is unavoidable! In other words, a root-bound plant will tend to come into flower better than one that is not.


Q: What would be a good choice for a low-maintenance, perennial ground cover for an area that receives limited direct sunlight and is in a somewhat drought-prone area of southwestern North Dakota? The soil is somewhat compacted. I would prefer prostrate/semiprostrate growth. If the growth is upright, then I'm looking for a cover that is short (less than a foot tall). Also, what would you suggest for a tall-growing, ornamental perennial grass that only receives morning sunshine? (Dickinson, N.D.)

A: Thanks for some easy questions! There are no "good plants" that I know of for the situations you describe. However, you might want to consider liatris, sedum and sea thrift (Armeria spp), but I make no guarantees. As for the grasses, try a species of miscanthus sinensis, feather reed grass - calamagrostis stricta or switch grass - panicum virgatum.


Q: So far, I have received six unrequested seed catalogs for flowers, vegetables, trees and shrubs. I am sure more are on the way! What can you tell me about making a choice as to which catalog to purchase from? They seem to have similar or identical varieties and a wide variation in prices. (Fargo, N.D.)

A: Welcome to the fold! I have a file full of garden catalogs. Of course, there is no way to order from all of them. Jot down what it is you want in your garden this year along with the quantities you want. Order just that and nothing more! Americans are a very gullible lot, so typically we order at least twice as much as we need. Most catalog companies have good quality products, so pick one or two that seem to have products that are the most pleasing to your tastes.


Q: We have a sloped area in our yard. We’re looking for a flowering, low-growing ground cover. It’s in a sunny area and has good soil. What do you recommend? Also, we have a lot of crabgrass and quackgrass. What would you recommend to control it and when to apply it in the spring? We enjoy reading Hortiscope. (Browns Valley, Minn.)

A: Thank you, I’m glad you enjoy the column! Quackgrass is going to be difficult to control, but give it a try. Next spring before you plant, spray the quackgrass with Roundup when it is 3 to 4 inches tall. That will at least slow it down. Chokeberry, bird's foot trefoil, moneywort and lily of the valley are some plants you may want to consider. Thank you for your interest!


Q: I have an underground oil tank that I intend to have pulled out. On top of the tank are four magnificent 20-year-old rhododendrons. Can I have the tank removed during the winter while the soil is frozen and the plants dormant or it is better to do it in the spring? Are there any particular measures that I should take before or after this operation to protect the plants? When I replant them, should I trim them back severely? (e-mail reference)

A: There isn’t a good time for removing plants that old. One season is as bad as the other, so you might as well go for it during the winter months while everything is dormant and frozen. Try to dig up as much of the root system as possible. Keep the plants frozen and out of the sun. Replant at the same depth and oriented the same way immediately after the tank is removed. Mulch, don't water and keep your fingers crossed that this idea works.


Q: My anthurium has not bloomed since I brought it home from the store a year ago. Every leaf has brown edges, which I trim often. It is not in direct sunlight, so I do not believe it is getting too much sun. (e-mail reference)

A: Anthuriums are plants from the heart of the tropics, so they require about 80 percent humidity and 80-degree temperatures or better to thrive and bloom. Light sun is OK, but not direct, hot sunlight. Filter the sunlight through a sheer curtain if possible. In their native habitat, these are plants that thrive under the canopy of a tree. Typical home environments usually are too dry and cool to encourage much blooming of these beautiful plants. I have some suggestions if you want to try to mimic tropical conditions around the plant. Place a humidifier and space heater near the plant. Place the plant on top of a large tray of pebbles covered with water. Try fertilizing. You didn't mention if you did or not. Look for a blooming type of fertilizer that is high in phosphorus. The middle number should read something such as 15-30-15. Use it about once a month. This, along with some environmental manipulation and patience, should produce some blooms.


Q: A friend gave me some seedpods from what I believe is a datura she had growing in her yard. Do the seeds need to be frozen or chilled before they will germinate? Also, my son grew a Texas bluebonnet for me. It grew well and bloomed profusely through the summer. I have it in a pot now that Bismarck is headed into the deep freeze. How do I care for it? The plant is losing color and looks like it would benefit from a trim. I also would like to germinate this plant as well. Any suggestions? (Bismarck, N.D.)

A: Datura is an annual. If the seed is viable, it will germinate under the right heat, moisture and light conditions. As for the Texas bluebonnet, it is a wildflower and hardy to zone 7, which is three or four zones south of North Dakota. The seeds need to be scarified and planted somewhere where they can get chilled. An option is to store the seeds in the crisper of your refrigerator.


Q: After our purple coneflower bloomed, green growth began coming out on the remaining uncut cones. It looks as if little, green plants are growing on the cones. What is this? (e-mail reference)

A: These are seedlings coming up in the cones that didn't get expelled from the cone. Don't worry, most will survive after they fall to the ground. This is a very self-perpetuating species.
If you want, you could help them by trying to shake them loose and popping them into the soil.


Q: I know a couple who purchased some beautiful mums, but they are wondering what they should do with the plants. Should they plant them or overwinter them in their pots and plant them next spring? I suggested that they set the plants outside for now and then bring them into an unheated garage for overwintering. If they can plant the mums, what should they do to ensure the plant’s survival during the winter? (e-mail reference)

A: Planted indoors or out, there are no guarantees the plants will survival. Right now, they would be better off planting the mums outside and watering them in. Mulch the crowns with straw after the first freeze.


Q: What is the difference between a water plant and its landlocked cousin? As an example, I purchased water canna and then was told that standard canna could be used in a pond the same as water canna. Is this true and can it also be said of calla lily and iris, or do you have to purchase the specific water calla lily or water iris? (e-mail reference)

A: First, I'll have to admit that I am not an expert on aquatic plants, but I doubt that the same canna that is used in landscaping can be used as a pond plant. The same goes for the other two you mentioned.


Q: I read your article about digging out plants and then using Roundup to get rid of unwanted mint. Does that mean I have to dig up everything, including my rose bushes? (e-mail reference)

A: Mint is very vulnerable to Roundup. You can approach your problem a few different ways. Protect the plants you want to save by placing a plastic bag over them when you are spraying with Roundup or remove the plants you want to keep that are above the soil surface and spray the Roundup to your heart's content. Since Roundup is not soil active, it will not affect the bulbs as long as there is no green foliage showing.


Q: I planted cannas in large containers in front of my house. They gave me a very nice show of foliage and flowers this summer. I would like to replant them next year under the same conditions. When should I cut off the foliage and how should I try to preserve the rhizomes for use next year? Do I wait for a hard frost and then cut the plants down or stop watering and wait for them to dry off? Thank you. (Bismarck, N.D.)

A: Allow the cannas to dry down a little and then let a frost blacken the foliage. Dig up the plants and bring them indoors. Shake off the soil, but don't wash it off. Place them in a basket or netted bag with dusting sulfur and store them in a cool location for the winter.


Q: I purchased a PJM rhododendron, a northern lights variety of azaleas and an endless summer hydrangea. I lost them all to root rot by overwatering. Imagine overwatering in South Dakota, which is having the worst drought in the last 25 years. Can these same varieties be planted in the same location next spring? I'm concerned with bacterial spores remaining in the soil/peat mix. Thank you for your expertise, you offer a great deal to our gardening society. Bless you. (Mt. Vernon, S.D.)

A: Thank you. I’m glad the information is useful! To be on the safe side, I would remove the soil and replace it with dirt from another location. It would be frustrating to replant and have the same thing happen again! From a plant pathology standpoint, it is never a good idea to replant in the same location with the same species of plants.


Q: Your Web postings are very helpful. Is there a spray that I can use to kill grass in my ornamental poppies and peonies? Also, my hollyhocks seem to get brown leaves from the bottom up. Lastly, my petunias never seem to bloom profusely and last the summer. Any suggestions? Thanks for your help. (e-mail reference)

A: Glad you find the postings useful. It would help me if you could give me a better description of where you live and what the site is like. Is the area shady or sunny? What is the moisture content, wind exposure and soil type? What type of cultural practices do you use? I do have some answers based on what you have told me. Hi-Yield Grass Killer is a common product on the market that contains sethoxydim. If you cannot find that particular brand, then check any grass killer brand on the market that has sethoxydim as the active ingredient. Hollyhocks are wonderful hosts to a plethora of fungal diseases, but I don’t know which one you are referencing. Protective fungicide sprays are needed to keep the fungal diseases in check, before any symptoms show. I suggest hand removing the symptomatic foliage and spraying the rest of the plant with a locally available fungicide. Petunias need full sunlight, plenty of moisture and ample fertilization in well-drained soil in order to show their best.


Q: I heard that if you cut down dianthus after it is done blooming, it will grow and bloom again that same summer. Is there any truth to that story? (Valley City, N.D.)

A: Yes.


Q: I have never used chemicals in my garden and never want to, but this was my last resort. My garden was almost gone! I used Ortho's Isotox Formula IV on my garden (all plants). The smell was horrible. It still smells bad after three days and some of my plants are wilting or turning brown. Is this product killing my plants? Can I do something before I lose all my perennials? (e-mail reference)

A: If you read and followed label directions, you should not be having this problem. You didn't tell me where you live and under what conditions you made the application, so I can't advise you any further. Isotox should be a selection of last choice to control insects because of the reasons you mentioned, along with the high toxicity it has.


Q: What do full sun, partial sun and light shade really mean? If full sun is six hours of sunlight, does that mean six continuous hours or could it be three hours of sun, a period of shade and then more sun? Maybe I'm being too uptight about the sun thing, but I don't want to plant something in the wrong spot and have it not thrive. I'm starting new flower beds and would like to get it right from the beginning. (e-mail reference)

A: Full sun means a straight six hours or divided up as you state. However, experienced gardeners know that not all sun is created equal. Morning sun is cooler and less stressful on plants than midday or late afternoon sun. Also, it is well known that reflective sunlight can be even more damaging to plants. I would say you are being a little uptight about all of this. You needn't be because gardening is not an exact science. Gardening is a combination of science and art, which makes it enjoyable and exciting to see how things turn out. In other words, there are many paths to success! Use common sense and ask experienced gardeners what has worked best for them on any plantings you question. I have yet to meet a gardener who isn't anxious to share his or her knowledge!


Q: My mom and brother have new plants that they want me to learn how to take care of. One is a sunflower and the other is a passion flower. How often should they be watered and how much water should I use? (e-mail reference)

A: If they are in containers, they will need different care than if they are planted outdoors.

Sunflowers, as the name implies, need full sun and about 18 to 24 inches of precipitation during the growing season, especially early on to get some growth started. Once sunflowers head out, the requirements for water are reduced. If you live in a temperate zone where freezing occurs in the fall and winter, the plant likely will be killed.

Passion flowers also like full sun, but cooler temperatures than sunflowers. This is more of a houseplant than an outdoor plant. For the summer, it would thrive outdoors in an eastern setting and the temperatures didn't get too high. It needs to be kept evenly moist during the active phase of growth, which usually lasts until early fall. Then back off on the water, but don't allow the rootball to dry completely.


Q: I've had a question about Russian sage. I'm not that familiar with the plant other than what it looks like. Can it be trimmed and when is the best time to do it? (LaMoure, N.D.)

A: Russian sage should be cut back in early spring. Leave 3 to 4 inches of growth.


Q: Can you tell me where to purchase indoor house plants, such as baby tears, piggyback and all the ivies? I am in a wheelchair and can’t get outside to plant flowers, so I like indoor plants. Please help me. (e-mail reference)

A: Go to www.waysidegardens.com for the Wayside Gardens catalog. Wayside Gardens is one of the world's largest mail-order sources for plants of all kinds.


Q: For Easter, I received a lovely basket containing daffodils, hyacinth and tulips. The flowers have now died. Can I transplant them in my yard for next year? If so, how would I go about doing this? They are in little, individual pots. I don't know if I made a mistake, but I did cut the dead flowers off. I thought I read somewhere that if you leave the flowers on, the plants will start to seed, therefore not giving any nourishment to the bulb for next year. Should I dump the plants or is there still hope? (e-mail reference)

A: You are doing OK. Allow the foliage to die down naturally. Keep the plants watered and in sunlight until then. Once the foliage has dried, remove it and store the bulbs in a cool, dark location until this fall. Sometime around Sept. 1 through 15, plant the bulbs outdoors where you want them. The plants should bloom for you next spring.


Q: I want to do a bed with rose bushes by a wall. In front of the roses, I want to plant irises, daylilies and tulips. In the very front, I would like something small, such as pansies. What would happen if I planted the bulbs in circular patterns or something similar? Would some of the plants be hidden? Do the plants have to be certain distance apart? I just don't want straight lines of flowers. (e-mail reference)

A: Lay out a bed shape with a garden hose, kicking the hose in and out to create a free-flowing curve or curves. Then plant as you described, with the exception of the daylilies being in front of the roses because their foliage may get big, depending on the cultivar. You don’t want covered or partially hidden rose plants because they need as much direct sunlight as possible.


Q: I have two, large indoor plants (Spanish bayonet). Do they ever bloom? Some of the leaves have developed small, dark brown hard spots. What are these spots and what can I do about them? (e-mail reference)

A: They will bloom, if you summer them outdoors so they get more sunlight. I never have seen or heard of one blooming indoors, unless someone had them situated where they could get maximum direct sunlight. Those hard, dark spots could be San Jose scale. See if they scrape off and leave a little pin hole behind. You'll need a magnifier, unless you have eyes like a hawk! If they are confined to just a leaf or two, cut them off and dispose of them.. If there are a lot of spots spread on many leaves, then you need to get a systemic insecticide that can be used on these plants. Shop for a product known as Meta-Systox (or others). Read and follow the label directions before using.


Q: I have a bromelaid plant I got from my daughter two years ago. It had a pretty, pink flower when I received it. The flower lasted a long time before it fell off. The plant looks healthy, but it is in a small, plastic pot that would not stand up alone. I feel it needs to be transplanted into a larger pot. Will it ever bloom again if I do that? Any help you could offer on the size of the pot I should use for transplanting and what fertilizer to use would be greatly appreciated. (e-mail reference)

A: A clay pot is always better than a plastic one. What you need to do is go up to the next size pot. If it is in a 4-inch pot, go to the next size larger, which is a 5-inch pot, but don’t go any larger. You always can cut the plant back to keep it from falling over. Plants that produce a bloom will do so again when it has enough stored energy. Make sure it is getting enough light (a deficiency would be stretched and/or weak stems) and is not overwatered. The time to fertilize is when new growth is evident. Fertilize about every two weeks with a diluted solution of any good houseplant fertilizer.


Q: I live on a farm with a large flower bed that is not well protected from the wind and gets a lot of direct sunlight. I would like to know your opinion about mulch. What is the best mulch to use that is readily available, doesn't have a lot of side effects and is relatively inexpensive? I have access to wood chips, but am concerned about the pros and cons of using wood chips. I also would like information on ornamental evergreens and conifers. I have seen several in seed catalogs that are weeping and some that are more blue or golden, but I do not always trust the information given in these catalogs. Also, I like the unusual look of the walking stick and the curly willow in the winter, but understand that both are not that great to look at in the summer. Is there anything that looks great throughout the year? I look forward to your column every week and appreciate any advice I can get from you. (Jamestown, N.D.)

A: Thanks for being a faithful reader of the column! You can use wood chip mulch without adverse side effects if the mulch has had a chance to cure or compost for at least one season. The exception might be black walnut chips if you are going to grow tomatoes or other members of this family. Just don't exceed 3 inches in depth. The evergreens that are common in our area are the Colorado blue spruce. I would encourage you to steer clear of that species and look into something else, such as Black Hills spruce, ponderosa or Swiss stone pine. For anything to look great throughout the year is a tall order. How many humans do you know who can make that claim? However, the river birch looks great throughout the year, as does the copper curls pekin lilac. The exfoliating bark on both plants is an attraction throughout the year.


Q: Several years ago I planted snow-on-the-mountain in my flower beds. It has now become very invasive. I wish to eradicate the plants because I am getting tired of spending the summer trying to keep ahead of the runners. Any suggestions would be appreciated. (Fargo, N.D.)

A: The only solution I can think of is to use a glyphosate – RoundUp - this spring as new growth begins. It will take repeat applications, so don't lose patience.


Q: Which version of campsis radicans does best in Grand Forks? Also, what are your five best perennials for attracting hummingbirds and are hardy in Grand Forks? (e-mail reference)

A: I would encourage you to contact Steve Sagaser, Grand Forks County horticulturist, for more details beyond what I will give you. He can be reached at stevan.sagaser@ndsu.edu. To my knowledge, the trumpet creeper is not dependably hardy in the Grand Forks area, but this is where Steve would know better than I would. As for the perennials, I can give you some tough ones that I've planted here in the banana belt of Fargo that should do equally well in Grand Forks. They include anise hyssop (Agastache foeniculum), bee balm (Monarda didyma), delphiniums (Delphinium spp.), cardinal flower (Lobelia cardinalis), geranium (several cultivars) and daylilies (Hemerocallis spp.). Prairie gayfeather (Liatris spp.) also should survive in your garden because it is native to our region. Perhaps Steve can add or correct this list for you.


Q: We have a small plant on the south side of our house. It gets very hot and dry there, but it seems to be doing well. The person I got it from called it a "gas plant" because it has a very strong odor. It flowers in midsummer with pink blooms. If you can, please let me know the name of this plant. (McLeod, N.D.)

A: I’m glad to hear that it has done well for you. It is botanically known as Dictamnus albus and is the cultivar Purpureus, which has the purple/pink flower. The Rubrus cultivar has red flowers. Be sure to plant it where you want. They are not keen on being moved.


Q: In preserving flowers with antifreeze, do you mix it with water or use it straight? (e-mail reference)

A: The ratio is two parts water to one part antifreeze.


Q: I am trying to locate cloudberry seeds or the plants. I know they grow in Alaska and Vermont, as well as Canada, Finland and Scandinavia. Any suggestions on where I might be able to purchase these plants or seeds? (e-mail reference)

A: Try the St. Lawrence Nursery in Potsdam, N.Y. E-mail the nursery at trees@sln.potsdam.ny.us or call (315) 265-6739. Its Web site is www.sln.potsdam.ny.us.
This is a small, organically run, family-owned business. Bill MacKentley is the proprietor. He knows his plant material and delights in growing some fringe material. If he doesn't have it in his nursery, he might know someone who would be able to supply it for you.


Q: I planted a Pagoda dogwood last August and amended our horrible clay soil with sphagnum peat moss and compost from the Fargo recycling facility. Not long after planting, the leaves began to curl, turn black and drop off. There were no signs of insects or disease and I provided adequate water. New growth soon emerged, but suffered the same fate up to fall frost. Is the nitrogen content of the compost from the landfill abnormally high due to fertilizer application? Could that have caused the burning and leaf drop? (Fargo, N.D.)

A: It sounds like a total dissolved salts problem. The likely source is the compost. Years ago, I ran a salt spectrum on the material and found it to be abnormally high. I usually recommend that no more than 10 percent to 15 percent of the compost be used in any planting mix because the nutrients are high enough to cause the burning you describe with many plant species. Chances are the Pagoda dogwood will recover this spring, given the amount of moisture we had this fall and the subsequent snowfall we’ve had. You can use the city compost, but do so in limited amounts because of its nutrient-rich character.


Q: I used to have a snake plant in my old house. I had it for more than 13 years, but I was moving to a house with poor lighting, so I gave it to my neighbor. It never flowered the entire time I had it, but I miss it! After I moved, I discovered that I had a perfect window for plants and a new friend gave me a cutting that I was able to grow. I’ve had it for more than a year. The plant lives in a bathroom window (southern exposure) near my shower stall. Tonight, when I went to see if it needed water, it was blooming! I thought this happened in February. When will I get the berry (fruit)? I saw that you told someone to cut off the bloom. Why should I do that? I never water the plant until it grabs my leg when I am leaving the shower! (e-mail reference)

A: It sounds like a fresh snake plant to me. Are you sure you want it to be in the bathroom with you when you shower? Blooming can take place anytime the energy reserves are at a high enough level to do so. Also, some blooming depends on day length. Some bloom during long daylight hours (short nights), while others bloom on short days (long nights). Others are indifferent and bloom whenever conditions within the plant will allow it to do so, as in the case of your snake plant. Putting energy into fruit production is wasteful with houseplants, especially the snake plant because it spends most of its life as a foliage plant. Admire the bloom while you can, then remove it as the flower begins fading.


Q: I purchased a large number of bulbs this fall, but was only able to plant a small number of them. I saw your response to another question that the bulbs can’t be saved for another year. Do you have any suggestions about what to do with them? Could they be planted in pots and placed outdoors during the winter? Could they be placed in pots in the basement and transplanted in the spring? (e-mail reference)

A: At this stage, go ahead and plant them in pots or containers. Place them in as cool a location as possible, even outdoors. Under straw mulch on the north side of your house would be ideal. Then as spring approaches and the temperatures climb, you can uncover them and enjoy the blooms wherever you want. You can try keeping them separately in the crisper of your refrigerator until the frost leaves the ground (they'll likely be sprouted by then) and then plant them. I'm afraid that if you planted them in pots and placed them in the basement, they would blast into bloom and be wasted, along with being a mess to clean up.


Q: I found some Wilt Pruf at a local store. On the label is says, "For winter protection: When spraying on arborvitae, etc., be aware that if these species have not sufficiently hardened off for the winter, whereby moisture retreats to the root system, moisture in plant cells could freeze and burst if early severe freezing weather should occur." What is hardened off? When do you feel it is safe to apply? Should it be used liberally? (e-mail reference)

A: Hardening off is a term used to describe plants that are exposed to the elements coming into the winter or, as in the case of annual flowers and vegetables, our "normal" North Dakota spring weather. To be safe, the plants probably should go through a few more cold snaps and the material applied on a day when the temperature is 40 degrees or higher and a Manitoba clipper is on the way in a few days.


Q: What can I do to my gladiola bulbs after I dig them up to kill the thrips that have invaded my garden? Is there something I can treat the bulbs with that will kill the insects and their eggs without hurting the bulbs? I am afraid there will be further damage during winter storage if I don't fix the problem. (Valley City, N.D.)

A: Dust the bulbs with sulfur powder. Place the bulbs in a paper bag with the sulfur and shake well to get it into the openings. Store the bulbs in the bag. If the thrips survive, move out!


Q: Why do all the sunflowers I see face east? I thought sunflowers were supposed to follow the sun or is that just a “rural myth”? (e-mail reference)

A: It is not a rural myth. Sunflowers turn their heads to follow the sun while they are developing. Once developed, they lock into facing east.


Q: What plants can replace purple loosestrife, if homeowners want to get rid of it and replace it with something that looks like purple loosestrife? I know you have written about it, but I can’t get my hands on that information. (e-mail reference)

A: No problem, I do that all the time! Several plants can be used as substitutes and in many ways are better than the non-native loosestrife. They are: blazing star or gay feather, Liatris spp; bugbane or black Snakeroot, Cimicfuga racemosa; (I’m growing this one and love it!) cardinal flower, Lobelia cardinalis; lupine, Lupinus spp; penstemon, Penstemon spp; Russian sage, Perovskia artriplicifolia; salvia, Salvia X suberba and S. sylverstris; and spike speedwell, Veronica spicata. Any of these would be worthy replacements!


Q: In the fall, is there a rule of thumb as to what plants, such as tea or shrub roses, mums, hydrangea, hibiscus or strawberries, to trim back or cut to the ground? (e-mail reference)

A: Don’t get too anxious! Wait until a good, hard frost renders them dormant for the season. Then, the cultured roses and peonies, along with the hydrangeas, can be cut back. The latter two can be cut off at ground level, while the cultured roses should be cut back to about 6- to 8-inch stubs and tipped and buried or heavily mulched and covered with soil before the seriously cold weather arrives.


Q: I have a lipstick plant that hasn’t bloomed since I bought it last spring. I have it in the south hallway of my house. The hallway has floor to ceiling glass doors and windows. It gets light, but not direct sunshine. Should I give it more light? I water it when it gets dry. (e-mail reference)

A: These plants require a little patience to get them to flower. They need bright light, but not direct sunlight. They also need to be kept watered well during the spring and summer months and watered sparingly in winter. Mist the foliage when the air is dry or temperatures are very high. Repot the plant every two to three years.


Q: I have several bags of cocoa bean mulch that I plan to use on my flowerbeds. Since then, a friend told me it isn’t good for all plants and that it is poisonous for dogs. I don’t have a dog, but do have outdoor cats. I can’t find any information that says anything about cats. Do you know if it is bad for cats and what plants it shouldn’t be used for? (e-mail reference)

A: It is lethal to dogs and cats. It smells like chocolate, which really attracts dogs. They will ingest it and die. It is the theobromine in chocolate mulch that makes it so attractive to dogs. Theobromine acts as a stimulant, similar to caffeine. Dogs will eat anything short of a discarded tire. Cats are little more selective, but may use the mulch as a litter box. It is a shame that cocoa bean mulch has this toxicity.


Q: Is there a weed control that I can use in my flowerbed that won’t kill my flowers? (e-mail reference)

A: Use a product called “Preen,” which is available anywhere in the U.S. and Canada. The area needs to be cleanly cultivated and then the material applied according to the directions.


Q: We will be placing window boxes around one of our local buildings - on the east and west side, easy wave petunias and the north side a mix of impatiens and begonias. A watering system is being installed to water each basket daily. How often should we fertilize? Some say a low dose each day, while others say two doses of clean water and feed on the third day. (e-mail reference)

A: A low dose every day would be best, if you are good at making low doses. Miracle-Gro fertilizer is about as good as it gets for this purpose.


Q: I have a coleus plant with burgundy or red leaves and green on the flowers. I watered it the other day because it was drooping. It did well after watering, but within days some of the leaves became pale or faded. What does this mean? Will the plant die? (e-mail reference)

A: The plant likely is in too much shade. Try giving it a little more light, but not too much all at once.


Q: Have you seen a houseplant that looks like a dolphin? I do not know the plant’s name, but would love to have one. (e-mail reference)

A: I posed the question to my bright, young colleague, Lisa Duppong. She came up with your dolphin plant. The plant is known as a dancing dolphin vine and comes from the Michigan Bulb Co. Its Web site is at http://michiganbulb.com/item_disp.asp?pn=68593.
It looks like a showy beauty, so enjoy!


Q: I had a rhododendron that did not make it through the winter. It was fine in the fall and had beautiful blooms. It was on the south side by a fence and got afternoon sun. I dug it up and found small green balls in the soil. I did not fertilize. In addition, the hydrangea I planted last year did not grow back very well. I had aphids last year, but I sprayed. What can I do to make them healthy and what would cause my rhododendron to die? (e-mail reference)

A: Don’t plant rhododendron in direct sunlight and be sure to modify the soil with a lot of sphagnum peat moss. I would suggest a little more patience with both. Give them a shot of Miracle-Gro when growth begins.


Q: A member of a compost e-mail list recently said that compost is a good, natural form of weed control and enhances the soil, particularly clay soils. I understand how compost can enhance the soil, but I question the use of compost as form of weed control. What has been your experience and are there any studies that support using compost to control weeds? (e-mail reference)

A: If the compost is weed seed-free and applied to a depth of 3 to 4 inches, it will block light, which is required to get most weed seeds to germinate. That is the limit of its effectiveness. It works, up to a point.


Q: I’m writing for my daughter who lives in Mandan. She is interested in planting a small shrub row next to her home. The planting area is on the south side of her home. The planting area measures 46 inches wide by 35 feet long. Next to the planting area is a paved alley, which creates a lot of heat. Is there a shrub that can be planted that will take the heat or should we plant something else? Do you have any other suggestions? I read your column faithfully and respect your suggestions. You do such a wonderful job! (e-mail reference)

A: Thank you for the nice comments about the column. I appreciate you being a faithful reader and enjoying what you read. I wouldn’t bother with shrubs, if you don’t mind. I would suggest that your daughter get a prairie wildflower mix. It will explode into a riot of color that will grow back each year. The flowers need little maintenance, just an annual mowing before new growth begins in the spring. Wildflower mixes are available at local garden supply stores or through catalogs. If she has any trouble locating a source, let me know.


Q: I was in your square-foot gardening session at the recent Perham gardening day. I got a used copy of Mel Bartholomew’s book and was all set to try a couple of “squares.” Then I discovered vermiculite is no longer available in the Detroit Lakes area. A fellow at a local store even made calls to several suppliers, but no one carries it. Is there someone in Fargo that has it or should I use more peat as the book suggests as a “not quite as good” alternative? (e-mail reference)

A: Vermiculite is off the market. Peat is as good or better in my opinion, so go ahead and use it. Enjoy the bounty you will get from the plantings this summer! Thanks for attending the class.


Q: I have a new perennial bed I planted last spring and mulched last fall. When should I remove the mulch? When is the best time to prune shrub roses? (Arlington, S.D.)

A: You should be able to pull the winter mulch off the crowns now. If you are the least bit paranoid about the weather, leave the mulch between the plants in case the weather changes for the worse. That way you can quickly pull the mulch back over the emerging growth coming from the crowns. Pruning is best done at this time of year before the emergence of new growth, but avoid the simple act of “topping” any plant material because it destroys the natural shape or form of the plant.


Q: Could you please tell me how to store moon flower seeds for planting next spring? (e-mail reference)

A: Put the seeds in an air-tight jar and store them in a cool, dark location, such as the basement.


Q: My sister teaches in Dickinson. She has access to the school greenhouse and is planning on using it this spring. She hopes to take her seedlings there at the time she transplants them. To her knowledge, the greenhouse has never been cleaned. She remembers that last year she had some insects when she brought her seedlings home. What is a good way to clean the greenhouse? She also says that dandelions and weeds are growing there. What should she do to kill them? (e-mail reference)

A: As far as cleaning up a greenhouse, been there and done that! Without using chemicals, physically get rid of all the weeds. Dig or pull them out. I am fearful of residual from any herbicide that could be used for control being carried over to the intended crop. Next, tell her to put on rubber gloves, protective mask and goggles and mix up a 10 percent bleach solution. Scrub or wash every surface possible, then seal up the greenhouse for a week with the heat on. After a week, rinse the surfaces with plain water and then start planting, but use pasteurized soil. Try to follow good hygiene through the entire planting and management process. She may want to hang up yellow sticky traps to monitor insect activity. That way she won’t get any nasty surprises, such as a sudden outbreak of plant munching-bugs!


Q: I have a single-stem yucca plant. About a month ago, the lower leaves started turning pale green and then yellow and dying off. I removed the dried leaves and repotted it using general compost. I always thought my watering regime was fine, but after I repotted there was some excess water in the bottom of the pot. Could I have damaged the roots by overwatering? I have never fed the plant until yesterday using some slow-release pellets in the compost. Should I start over with another plant or is there a way to bring my plant back? Is it possible to cut the stem back to get it to grow? (e-mail reference)

A: Attempting to grow a plant in a nondraining container is a mistake that many amateur gardeners make. There ought to be a law against such sales! Repot the plant in a free-draining pot. Place a saucer under it to collect the drained water. Dispose of the excess water 20 to 30 minutes after watering. Yucca thrives in the dry lands of our country because it needs very little water. When you think it needs watering, wait at least 24 hours before doing so. Even after waiting that long, you still might be overwatering. The plant should perk up a few weeks after repotting. The plant eventually will produce new growth, which will allow you to cut back the gawky looking stem. In the meantime, those few remaining leaves are acting as competent emergency medical personnel by producing food to help the plant recover from being in a boggy root environment.


Q: I have seen people grow beautiful flowering and foliage plants in the same pot. I would like to know what kinds of flowering plants I can plant with spider plants to add color. I also have heard of spider plants producing their own flowers. Is there a type of spider plant that is more likely to produce flowers? (e-mail reference)

A: Spider plants are usually stand-alone plants because of the massive foliage, runners and spiderettes they produce. However, this shouldn’t keep you from experimenting and informing us of the results. You might want to begin with something that is as, if not more, aggressive than the spider plant at overwhelming a container. You may want to try a wave petunia.


Q: I have a lipstick plant. A few of the leaves are turning yellow at the middle. What could be causing this? (e-mail reference)

A: It could be that the water that is applied is too cold or the plant is getting too much light. Lipstick plants should be located in bright, but not direct sunlight. Also, check the plant carefully for possible insect activity.


Q: In a recent column, you said that your answers regarding orchids came from research because you aren’t as educated about them. I may have an Internet site that can answer your questions about orchids (www.beautifulorchids.com). Troy and Isabella Woodcox own Beautiful Orchids, a San Francisco shop that sells orchids and helps clients take care of the plants. Click on orchid 101 to have your questions answered. (Bismarck, N.D.)

A: Thanks for the information! I’ll certainly use the site in the future. It is impossible to be knowledgeable about all things horticultural. In my early years, when I saw what it would take to know or be any kind of expert on orchids, I decided that I would leave that area of horticultural expertise to someone else. Thanks for being a faithful reader of the column!


Q: I have two hoya plants that are doing well, but they never bloom. I have had these plants for more than eight years. Is there something I can do to make them bloom? (e-mail reference)

A: Hoya plants are among the toughest plants to get to reflower. About the only thing I can tell you to do is give it more direct, bright light - sunlight if possible. More light translates into more stored energy from photosynthesis for reproduction (flowering).


Q: In the fall when I dig up my tubers, I dig up the whole plant and then cut off the plant, leaving about 2 inches of the stalk. I put a piece of tape around the remaining stalk to mark the tubers. The plants sometimes are wilted, frozen or still green. I have heard that the plants should be cut away after the first frost, but the tuber should remain in the ground for five to 10 more days. Sometimes I cut into one of the tubers of the clump, so I cut this tuber away from the clump and throw it away. Is this tuber still OK? As I mentioned, I use tape around the stem to mark the colors. However, often the tape comes off by the time I’m ready to plant. Can I use a permanent marker on the tuber? (e-mail reference)

A: You can dig up the tubers right after the first hard frost. The plant then is shut down physiologically for the season. Shake off the soil, and yes, you can use a permanent marker on the tubers. Any tuber will grow as long as it is healthy and there is a bud or “eye” at the stem end. If that end is broken off, it very likely will not produce a new plant.


Q: When I was in Fargo during early July, I saw many beautiful, pink rosebushes covered with blossoms. Can you give me some insight as to the name of this type of rosebush and type of care it requires? (New Rockford, N.D.)

A: Sorry, I can’t. Perhaps a reader will know what they are. If someone does, I’ll put it on my Web site and share the information in my column.


Q: I have two bougainvilleas that bloomed this spring and summer with many blooms. They are still covered with blooms. The leaves, however, are turning yellow and falling off. They over wintered in the house this past fall and winter. They even bloomed while in the house. I am doing nothing different from last year when they were healthy. I feed them every two weeks and water religiously. (e-mail reference)

A: The plant is probably attempting to go into dormancy because it needs a rest! Let it dry completely this winter by watering only occasionally. Next spring, as new growth begins to break, go back to your original watering cycle.


Q: I planted three yucca plants 25 years ago. They have blossomed into about 20 plants that all flower. I want to give some away. What is the best way of separating them, how should I do it and when? Also, I have a cherry tree that fruits every summer, but has put out runners in the yard. What can I use to kill the little plants but not hurt the grass or garden? When is the best time to separate and transplant peonies? (Valley City, N.D.)

A: Yucca can be replanted right now or any time the ground isn’t frozen. About the root suckers coming up from the cherry tree, the only thing you can try is some RTU Sucker-Stopper. It is available in Bismarck at Cashman’s Nursery. The suckers will drive you crazy before you get them under control. As for peonies, late-summer or early fall is the best time for division and transplanting. If you miss this opportunity, I have had some success with early-spring efforts.


Q: Do your readers know that triennials such as Angelica and heracleum can be kept living and blooming for years and years just by pinching off the flower heads after they bloom and before they set seeds? This may work with many other biennials and triennials as well. It isn't necessary to remove the seed heads from the side umbels, only from the large central umbel, so people who want seeds can keep their plants and seed them too. Heracleum lanatum (cow parsnip) is a very impressive, fragrant, native flower with foliage that’s attractive even before the plants are old enough to bloom. It is perfect for screen plantings, semi-wild areas and the back row of flower gardens, takes transplanting well, and grows readily from seed. I suspect it’s not cultivated very much because people don’t want to wait two or three years for it to flower once and die, but they don’t have to. I have kept some for ten years or more. (Valley City, N.D.)

A: No, I’m sure a lot of them didn’t! Thank you for the information.


Q: Can you tell me where I can get a Queen Ann’s lace plant? (Jamestown, N.D.)

A: Queen Anne’s lace, or wild carrot, is a member of the parsley family. It is considered a weed throughout the country. It may not be hardy for our area, but even if it was, I don’t think the weed control folks would want it getting established. In spite of the negative comments, this plant has a reputation as a medicinal plant and is marketed around the world by herbalists.


Q: Yesterday I purchased a mum plant at our local greenhouse. It is in full bloom and has several unopened flower buds. I would like it to also bloom in the fall, but the greenhouse workers gave me conflicting advice. One said I should shear off all the flowers and buds all summer if I want it to bloom this fall. The other worker said I should deadhead it and the plant should bloom all summer and fall. I hope it will come back every year, so I want to give it a good start. (e-mail reference)

A: Mum flowering is controlled by day length. Mums are genetically programmed to begin blooming during the short days of late summer or fall. The greenhouse operator likely limited light this spring to get them to set flower buds and be marketable around Memorial Day. If you deadhead or cut it back hard, it will not flower until sometime late this summer or fall, depending on where you are located and what cultivar mum you are working with.


Q: What is the proper way to store paper white bulbs during the summer and then replanting them for forced blooms in the fall of the second year? I currently have them in a paper bag in a cool dark place. (e-mail reference)

A: It sounds like you are on the right track. Check them occasionally to see if any are beginning to rot. Throw away those that are.


Q: I received some moon flower seeds with no instructions or history except they are reportedly poisonous. I would appreciate knowing if they are an annual or perennial, how deep to plant them and how tall they grow. (Brookings, S.D.)

A: Moon flower is like a morning glory in growth and form, but it opens in the evening instead of the morning and flowers only in white. The seeds are toxic, so obviously should not be eaten. Make sure children do not ingest them.


Q: Can you tell me if keeping flowers in a vase made of silver is good for them? I tried it once with tulips and they seemed to do fine, but when I finally threw them out, I noticed that the stems in the vase were completely shriveled shut. It looked like the plant was trying to keep water out. But, the tulips looked beautiful and lasted longer than tulips bought on the same day which were kept in a glass vase. Am I torturing the plant into lasting longer? (E-mail reference)

A: Silver thiosulphate is known to extend the life of cut flowers in a vase. I doubt the flowers are being tortured into lasting longer. Enjoy their beauty.


Q: I have a gardener that thinks you can plant hybrids, and if you save the seeds and plant them next year, they will revert back to their original variety instead of being a hybrid. I don’t think this is possible, but I have experience with animals, not plants, so I am just double checking to make sure. (Carson, N.D.)

A: The gardener was right. Hybrids are bred to produce a single generation with particular quality characteristics, such as flower or fruit size, disease resistance, height, time of maturity, flavor, etc. The seeds from those hybrid plants will be sterile or be a wide range of the parental line that went into making the hybrid.


Q: Is there anything I can do to get rid of grass growing in my perennial flower bed? The daffodils, poppies and columbines are coming up, along with the grass. I also pulled out some junipers next to my flowers. Can I plant flowers in the same spot or is the soil too acidic? (E-mail reference)

A: There are several products that are effective, but your planting mix may nix it by not being labeled for those particular plants. Visit your local garden center and see what is available. Most are effective when everything has been cleaned up. After clean up, a pre-emergent like Surflan can be put down. You can plant in the same location where the juniper existed.


Q: My friend has a lipstick plant that she split in three but is not blooming. Can this plant be split and still bloom? (E-mail reference)

A: Yes, but you have to be patient.


Q: I need to get rid of a quaking aspen in my front yard. I understand that just cutting the tree does not work. (E-mail reference)

A: Have an International Society of Arboriculture certified arborist do the work for you. They can treat the stump, roots and anything else that comes up with a herbicide like Trimec.


Q: What is the best soil to use for growing annual flowers in large outdoor pots or whiskey barrels? Can I use garden soil or do you recommend potting soil?

A: Always use potting soil that has good drainage. If you don’t, you’ll be wrestling with that problem all summer long.


Q: I would like to start a few wave petunias in hanging pots. I am never sure if I have too many or too few plants per pot. Could you give me a general guideline? (E-mail reference)

A: There is nothing wrong with the pots looking too full, in my estimation, especially with something this beautiful. In a hanging basket, I suggest three plants per pot. They should cascade beautifully for you.


Q: Last summer I purchased a phalaenopsis orchid (moth orchid). It seemed to be doing great and has bloomed twice with up to five flowers (from the same spike). However the last set of blooms has been very wilted looking for a couple of months but are not falling off. It’s also sending out another set of buds from the end of the same flower spike. The leaves are wrinkled and have become limp, giving them a leathery appearance. There is only one good thick root while the others look somewhat decayed. I have it on a humidity tray and gets bright, indirect light from an east window. It is potted in loose sphagnum moss and I fertilize it with a weak orchid fertilizer twice a month or when the moss has dried out. I thought I was overwatering because of the root decay but the leaves still look leathery and have started to dry and brown down the middle. It still hasn't lost its buds and seems to want to produce more. Am I using too much fertilizer or overwatering? Should I cut off the flower stem and give the rest of the plant time to catch up? (Aberdeen, S.D.)

A: I admit that I am light years away from being anything resembling an expert on orchids. I do know that they need strong, indirect light for about 15 hours a day. Since it doesn't sound like you are depriving it of heat, humidity or improper watering, I would suggest giving it some artificial light with a grow-bulb for 15 hours a day until the sun returns to our region in about 90 days or so. I would also remove the spent flower blossoms.


Q: When and how can I best prune my crepe myrtles? (E-mail reference)

A: Prune them anytime after winter but before Aug. 1. Be careful that you don’t destroy the natural aesthetics of this beautiful woody plant. It’s known for its beautiful flowers, attractive bark and fall color. Prune the stems you want removed but don't cut back to a point on the stem that leaves a two to four foot stump; you will regret doing so.


Q: The person who sprayed my lawn for dandelions this fall used a small amount of Banvil along with 2,4 D. I was going to dig up a small portion of lawn this fall and turn it into a flowerbed. How long does Banvil stay in the soil? If I plant the flowers now, will they survive and flower in the spring? (Ashley, N.D.)

A: I would dig up the soil this fall and let it lay fallow over winter. Bring in a pot full of soil and plant a tomato in it. If there is a toxic level of Banvil present, it will show on the tomato plant because they are very sensitive to this product. If no symptoms appear, then you are home free. If the plant shows a reaction, then you have to excavate the soil or add activated charcoal to the planting area to absorb the chemical.


Q: I have a beautiful mandevilla vine that I don't want to lose to frost. Is there anyway I can winter it in the basement or somewhere else in the house? Should I cut it down or leave it the way it is? (E-mail reference)

A: Mandevilla vine can take the low 40's without a problem. I would suggest cutting it back to 12 inches or less and back off on the watering. If you can, find a liquid fertilizer with an analysis of 10 50 12 or something similar. This will not stimulate the growth so much as it will help to toughen the plant to survive the winter indoors. Allow the plant to remain outdoors as long as possible. Dig it up and bring it inside putting it in the brightest spot possible. Water it just enough to keep it alive. You do not want to stimulate too much new growth, as it will not do well in the dry interior of a home. Next spring, move the plant outside after the danger of frost is past. Expect any growth produced during the long winter months to be burned off. That is not the death of the plant, but a re orientation to a new environment the plant is going through.


Q: The salvias in a large perennial bed have faded and I would like to cut them back to the ground so other plants can show. Can I do it at this time of year? (E-mail reference)

A: If they were healthy and vigorous this past summer, then it should not be a problem.


Q: I just moved a Carol Mackie Daphne and am wondering if I should cut it back to reduce the stress while it settles in. I root pruned it prior to moving it but many of the smaller roots were lost when I planted it so I’m afraid the bush will die. (E-mail reference)

A: That type of plant is very fussy about the way it is treated. At this time of year, assuming you live somewhere in the northern half of the U.S., I wouldn't remove any more of the top than necessary as it is needed to produce carbohydrates that will help build the root system. If it dies unexpectedly, don't be surprised.


Q: We are moving from Bismarck to Ashley. We have flowers, shrubs and bushes we would like to transplant. We are moving in February so of course we can't transplant anything then. Is it possible to transplant them to a temporary location (like the garden) this fall and then to the permanent location this spring? We don't have the permanent location ready for plants. How soon should we transplant? Do they have to have a period of growth this fall? Could we put them in huge pots for winter storage? Will they freeze out if left outside? How much care do they need during the dormant stage? Some of the plants we would like to transplant are lilacs, peonies, rose bushes, lilies, irises, hostas, a variety of scrubs and strawberries. (Ashley, N.D.)

A: It sounds like you are cleaning out your present landscape and moving it to your new location! Don't you think it would be more prudent to simply purchase new plants? You are creating a lot of work for yourself but the choice is yours to make. The plants should not be dug up until they go dormant this fall. Leave as much of a root mass as you can comfortably handle. When you get to the new site, plant them temporarily in a trench at a 45 degree angle and cover the roots completely. After the soil freezes, mulch the area completely with straw and don't worry about applying too much. It would be best if the temporary planting site had an east or north exposure to keep the plants from thawing too early in the spring. When you transplant next spring, be sure to trim the aerial part of the woody plants back about a third of their length. Plant at the same depth they currently are and water in. You have a lot of work ahead of you. I’m glad it's not me! I still think it would be easier to start new with fresh plantings from a local nursery.


Q: I bought a potentilla plant about three weeks ago. It had pretty yellow flowers on it and looked healthy. I planted it in full sunshine as I was told to do. I watered it well after planting and have watered it several times since but it’s all brown and looks dead. I even sprayed it with Miracle-Gro. (E-mail reference)

A: I would take it back to the retailer and see if you can get a replacement. These are usually very tough plants. Unless you did something grossly wrong such as planting too deep, washing all the soil off the roots or allowing the roots to dry before planting, they should have transplanted from the container to the site easily.


Q: I have a sandbox in my back yard that I would like to convert into a flower garden. I planted some moss roses that are growing but not spreading out. The box is wedged between a 5-foot fence on the west side and a fort/storage shed on the east side. It gets direct sun for a few hours in the afternoon and early evening. Any suggestions on what will grow in sand or should I add soil to it? Any ideas as far as blooming shrubs or perennials? I'm not much of a gardener to be honest but I love things that bloom profusely and for long periods of time (Fargo, N.D.)

A: Mix in some good quality loam and plant some shade tolerant plants like pansies, wax begonias or nigella. Portulaca needs a full day of sunlight, not just the few hours they presently get.


Q: I've been hearing about a horticultural therapy movement. I think it sounds like a great program. Do you know of anyone in North Dakota who is involved with it? (Bismarck, N.D.)

A: Funny you should ask I have gone through some rudimentary training on horticultural therapy. A book by Simon Straus entitled Horticulture As Therapy is available. I encourage you to pursue your interest in some manner.


Q: Is it possible to propagate cinquefoil from a cutting off a mature plant? Are there some written guidelines I should follow? (Bismarck, N.D.)

A: Cinquefoil roots very easily using softwood cuttings (current season's growth). Set up a micro irrigation intermittent misting system and mix in a 50/50 peat/perlite medium. Dip the cuttings in a 1 percent IBA compound. They should root in a matter of weeks. Be sure to cut back on the water after rooting is initiated. It’s a piece of cake in most instances.


Q: Can I grow flowers in soil where rhubarb has been removed or should I have the soil replaced? (E-mail reference)

A: I've had no problems planting flowers where rhubarb once stood.


Q: I sometimes see references to using Roundup by painting it on the leaves of unwanted plants. Can 2,4-D be used the same way if care is taken to have it not contact desirable plants? I’m assuming a jug I have of concentrated weed killer is 2,4-D. It has three different variations of Dimethylmine salt of 2, 4-Dichlorophenox. The instructions say not to use the product for controlling weeds in flower or vegetable beds, around shrubs or ornamental plants. But I would assume that is a reference to application by general spraying of an area. I'm looking for something that may be more successful than Roundup in my fight against ladybells. Their root system is really something. I won't consider Trimec. (Bismarck, N.D.)

A: I have never tried it but can’t see a reason why it wouldn't work. Use rubber gloves and a throw-away paint brush. Good luck!


Q: I read your article about drying flowers with great interest. I’m looking for a way to accelerate and perhaps improve the drying process. What would be the effect of putting the flowers in a vacuum? Has any work been done in this area? (E-mail reference)

A: I have never heard of this as a method of drying flowers but have as a way of preserving them after the flowers have dried. Nothing ventured, nothing gained. Give it a try!


Q: Can you recommend a variety of lavender hardy enough to survive our winters? (E-mail reference)

A: About the only one that comes close is the munstead cultivar of L. angustifolia. It all depends on where you live in N.D., the microclimate exposure, and the degree of protection you are willing to give it during winter.


Q: I am looking for information regarding my hoya plant. It is blooming right now. Sometimes it can have up to 16 blooms at a time. My daughter would like a cutting from this plant. When is the best time to take a snip and do I put it in water with a fertilizer or root starter or immediately plant it? Do I want to cut a stem that has flowered before? How long should I cut it? I have another hoya plant that has not bloomed. Both plants sit by a west window. The leaves on the one that flowers are quite faded and it looks like it may be root bound. On the one that doesn't flower, the leaves are dark green and it is not root bound. (E-mail reference)

A: Spring is the ideal time to take a cutting -- about 6-8 inches long -- from mature wood that is not currently flowering, and place it in a 50/50 sand/peat mix with no fertilizer. Keep it damp, not soggy wet. As long as the plant is producing flowers, I suggest leaving it alone. The same holds true for the one that is not flowering. Hoya should only be repotted when absolutely necessary.


Q: I purchased two plant bulbs that came with instructions and two glass vases. I placed clear stone in the bottom and filled with water just below the bulbs. They bloomed once (one each bulb) and the leaves grew to about 18-22 inches but then started to droop and the blooms disappeared. Can you please suggest a solution? (E-mail reference)

A: It sounds like you purchased some paper-white narcissus bulbs which have done exactly what they were supposed to do. You can either throw them out or transplant them outdoors in a protected spot and hope they come back next year (Not very likely around here!).


Q: I recently bought a plant from a florist who said it was a hoya. It has leaves like a hoya, but the blooms are not starlike. The end of the stem has six blooms which are shaped like a long skinny bell and are yellow turning into an orange color. Two of the six are in bloom now. The card stuck in the soil said it was a black Pagoda. Do you know if this is or is not a hoya plant? (E-mail reference)

A: What you describe sounds like a hoya, but I cannot find a match for black Pagoda. That doesn't mean anything however, because new introductions appear faster than one can keep up with them. If you trust the florist, then it is probably what you were sold.


Q: I received a crown of thorns about a year ago and it flowers all the time. It has gotten very big. Do I need to repot it any time soon? (E-mail reference)

A: The crown of thorn needs to be repotted every other year sometime during the spring season. Congratulations on being so successful in growing this very dramatically beautiful plant!


Q: I have a coreopsis moonbeam that is getting worse each year. The plants are smaller and coming up later in the spring. When they do come up, the leaves are so light green that I give them a small dose of iron. It seems to help but not a lot. I planted a small pink coreopsis two years ago that never did grow. Since we have so much clay I've added compost, manure and some sand to get the soil in better shape. The plants get several hours of sun each day during the spring and summer. I can't figure out what it is that I'm missing. (Moorhead, Minn.)

A: Coreopsis needs well-drained soil and full sun. The nutrient status should be moderate as they get too tall and floppy with regular fertilization. From what you are telling me, you are doing enough of the right things that you should be getting blooms and survivability out of the plants.

Sorry I can't be more of a help.


Q: I have a bad problem with tomato blossom rot. I have been told it’s caused by a calcium deficiency. I have tried a foliage spray with mixed results. Is there some other way to address this problem? Also, my annual flower bed dirt has become so gumbo like that the plants will no longer root. I live in Crosby and the water comes from the city’s lime softening plant. I think this is part of the problem. I am going to replace the dirt and start over but I have to use the same type of dirt for replacement. What can I mix in with the native dirt to prevent this problem from recurring? (Crosby, Minn.)

A: Blossom end rot is a cultivar/environment interaction. Generally the cause is from overzealous cultivation that damages the roots and results in a reduced nutrient uptake. It could also be from a wide fluctuation of watering or rainfall. Finally, some cultivars in some climates are prone to this malady, at least with the initial fruit set, thought to be tied with cold soil or cold water in the root zone. But, since you told me that the water source is already softened, and most likely with sodium, the problem is that particular cation is in such high concentration that it is destroying the structure of the soil and negatively affecting the growth of your plants. You need to get another water source or treat the water with a RO unit to remove the salt. It will simply cause the problem again later on even with all the soil being replaced. Canadian sphagnum peat moss is an excellent soil conditioner, and I would suggest incorporating generous amounts into the soil to improve the tilth.


Q: I have planted some paperwhite bulbs that are doing well. I would like to know how to take care of the bulbs after the flowers are done blooming. How long do the bulbs have to rest before you can plant them again? (Battle View N.D.)

A: Paperwhites are the most tender of the narcissus bulbs. Once they have stopped flowering, allow the foliage to remain. Keep it in natural bright light until it deteriorates. Once that’s done, a rest for a few weeks would probably be in order. Then plant outside in pots or inside again for reblooming. I have no direct experience in reblooming paperwhites and none of my references have a time line on the required rest period either so I am giving you my best guess. They are definitely not hardy enough for outdoor planting in North Dakota.


Q: I would appreciate some suggestions regarding landscaping our yard. We have a home north of Bismarck on the Missouri River. We get lots of wind on the (west) river side and an unbelievable amount of cottonwood leaves in the fall. We love the cottonwood trees so I don't mind the leaves other than how it might affect the plants around the house. I planted tauton yews on the river side last year. They are doing very well. I planted some wild-flowers on the east side and they did very well last summer. However, they have been beaten down a little by the leaves and I am curious to see how they fare. The solid planting of wild-flowers made it very difficult to get the leaves out. We also planted tomatoes on the east side where they got lots of sun and no wind. They did well. Now I would like to plant some flowers to get summer color but am unsure how to proceed. I am looking for help on plant selection and placement. I like the solid-plantings for their low maintenance but the leaves are a concern. Any suggestions? (Bismarck, N.D.)

A: I suggest going for some tough, leaf-shedding annuals and perennials like the following:

Perennials:
Lupine
Delphinium
Oriental Poppies
Echinacea
Annuals:
Cleome (spider plant)
Iceland Poppies
Rudbeckia (Indian Summer especially)
Cosmos

Showier plants like the wave petunia series and geraniums will probably get covered too much by leaves based on what you are telling me. This should give you a start.


Q: I’ve had a gardenia for almost a year. It was in bloom when we bought it but it has not bloomed since. The card said not to fertilize. The plant has doubled in size but the new leaves are a lighter green. I understand it likes acid soil as do camellia and azaleas which I also have trouble with. (Elkton, S.D.)

A: Go ahead and fertilize with an azalea plant food fertilizer. Rebloom will take place when the plant is good and ready to do so which will probably be later in the year. Just make sure you do not do any pruning in the meantime. Good luck!


Q: I have a 25-year-old hopa flowering crab that blooms only every other year. Should I cut it down and plant a variety that blooms annually? How does one know which varieties flower annually? A local dealer told me that all flowering crabs are biennial. Is that correct? (E-mail reference)

A: It may be because of the heavy fruit bearing that takes place one year, resulting in a very light or no bloom the following year. I suspect something else is going on with your hopa crab, especially one that is 25 years old. Your best bet, since crabapples are so regional in their disease resistance, is to contact your local university extension service through your local county agent or the university campus to find out which cultivars do well locally. That’s the best solution since I don't know where you live and crabapples are so fussy about their locality.


Q: I received a bouquet of flowers from a friend. I put an aspirin in the vase when they started wilting. I’m wondering why aspirin helps at all. (E-mail reference)

A: Aspirin is made up of salicylic acid which lowers the pH of the water, preventing fungal and bacterial growth for a period of time. The water should also be changed daily or at least every other day and fresh cuts made on the stems.


Q: I picked up some rhizomes at a discount department store late this fall only to have it snow before I got them in the ground. How do I store them over the winter so they have the best chance of making it in the spring? How about daylilies? I thought the price was right. Maybe the bargain was too good to be true. (E-mail reference)

A: Store them in a cool, dry, dark location until you can get them into the ground. The same for daylilies. You probably will not get 100 percent survival but at least some will make it through. Discard any that are mushy or showing other signs of deterioration.


Q: Anniversary time. What is the best way to keep cut flowers longer that are in a vase of water? (E-mail reference)

A: Happy anniversary! The type of flower you select is important. Carnations last a lot longer than do roses but the message can be just as passionate! Getting a combination of pink carnations and white daisies bespeaks of your love. Pink carnations mean "I will never forget you," and white daisy means "loyal love" which you obviously have. You can throw in a red rose or two which means "passionate love" if you want to cover all the bases! If that doesn't answer your question, try anything that acidifies the water such as vinegar, unbuffered aspirin, etc. Also, changing the water on a regular basis is a big help! Making fresh cuts on the stems will keep the water flowing to the tops. The florist you purchase them from may have some more up-to-date materials that might be more effective. Expect the roses to fade first, but don't worry, that is no indication of a loss of passion. If you buy them with a tight bud they will last longer than if they are partially open.


Q: The leaves of my lambs ears have gradually been covered with white dots that look like white measles. Over time, the whiteness spreads over the entire leaf. Any idea what this can be? Worms? Aphid eggs? I had aphids over the summer but the plant kept growing. (E-mail reference)

A: No idea what the problem is, but I would suggest dipping the plant into a solution of insecticidal soap, assuming it is in a container and if not, spraying the material directly on the foliage. This is a safe insecticide to use and is often all that is needed for control. You can also cut out and destroy the leaves that are affected the worst and lightly fertilize to encourage healthy new growth.


Q: I have a question about leaf mulch in my perennial flower garden. I used a 3-inch layer of uncut leaves to mulch my flower garden this summer. It worked great, no big weed problem, helped keep the soil moist and no loose dirt flying around. May I keep it on over the winter and then add more leaves in the spring? (Leola, S.D.)

A: It will not hurt to allow the leaves to remain on over the winter and for you to add more next spring. Just be cautioned however, that depending on the degree of decomposition of the leaves, the C/N (Carbon/Nitrogen) ratio could be a little high in some cases and tie up the available nitrogen. This is not a problem unless some chlorosis is observed, and if so, simply add some more nitrogenous fertilizer to off-set the temporary problem. As with any mulch, you want to check to see that slugs are not moving in and taking up residence. If you can turn some of the leaves into the soil surrounding the plants, that would be good for both the soil and the plants (be careful to not damage the roots.) and bad for any slugs that may have begun settling down for a long winter's nap!


Q: I picked up some lamium (Red Nancy) at an end of season clearance and was wondering if it's too late to put it in the ground or should I over winter it in the house and plant it in the spring? (West Fargo, N.D.)

A: Not at all. Go ahead and plant it now (when the weather finally allows you to do so!). The plant's root system will continue to develop until some hard frosts put a stop to it. Just be sure to water and mulch the plants generously before freeze-up.


Q: I have a beautiful mandevilla plant that has blossomed all summer. How can I keep it through the winter so I can enjoy it next summer too? (Hatton, N.D.)

A: Keep the temperature above 55ºF, water sparingly but mist regularly. Keep it in bright light, not sunlight.


Q: It was so hot last spring when the spirea were done blooming that I didn't cut them back. Could I do it this fall before freeze up? Thank you. (Marion, N.D.)

A: You could, but it is not a good idea. You are better off doing it early next spring before the plant leafs out.


Q: I have a plant called Datura meteloides 'Cornucopaea’. Could you give me any information on care, when to prune, and so forth? No information other then that it is a sun loving plant, came with the plant. At present I have it in a pot, outside, on the south side, and it's blooming. However, before the blossoms open up completely they burn off. I have tried moving it to partial sun and the buds began to fall off. Also, how do they multiply? (Stickney, S.D.)

A: The datura you are referring to is a cultivar that will not open its flowers much beyond the tube stage, if at all. It thrives in sun and heat and can only be grown as an annual in the north.

All parts of the plant are poisonous so be careful that no children or pets handle the leaves, flower, or fruits. The fruit that is formed is how they multiply.


Q: Would it be safe to move my yucca plant now? (Fargo, N.D.)

A: Go ahead and move it with as much care as you can provide. They are pretty tough customers and have a high survival rate.


Q: Can you tell me if the leaves of Engleman ivy, peony or hosta are poisonous? (Cando, N.D.)

A: The Engleman and peony are suspect; the hosta has no references to any poisonings.


Q: Is there a reason for variegated plantings changing to nonvariegated over a period of three or four years? Are the nonvariegated more competitive? (Jamestown, N.D.)

A: Most of the variegated plants are sports or somatic mutations, having nothing to do with the sexual process of breeding. Consequently, the variegation that we see in most plants are only "skin deep" and are sometimes overcome by the basic character of the plant, reverting back to the original form. Sometimes, if the new growth shows non-variegation, it can be pruned out and the variegated growth will remain. A lot depends on the vigor of the plant, along with the planting site, care and the growing season.


Q: I have a honeysuckle that is 4 years old and has done beautifully. It was coming good, but noticed last night that the leaves are turning brown and curling up. Earlier this spring it froze, and it seemed to come out of that. We have had lots of rain so it was wet, but other years it has been wet and it never looked like this. I have another one I just planted last year and it is doing okay so far. Second question. A gentleman wants to put a hedge up on the south side of his place as he gets lots of wind. He wanted to know how fast growing spirea and caragana are? Any suggestions on this? (Cavalier, N.D.)

A: My only guess is the use of an herbicide around the particular honeysuckle, if there is no evidence of insect activity. The bridal wreath spirea is a good choice. It’s tough as nails and will grow rather quickly, given some water and fertilizer.


Q: A while ago you gave an address and phone number for Park Seed Company. As I have lost my copy, I was wondering if you could share that information again. (Hawley, Minn.)

A: Gladly! Their number is 800-845-3369 and the website is www.parkseed.com.


Q: I'm trying to propagate cuttings from a bleeding heart and a vining honeysuckle. I plan to taking cuttings about 6 to 10 inches long, dip them in rooting hormone and put them in a starter mixture of soil, and cover the top with a plastic bag. Is this correct for both types of cuttings? If not what else? And what about temperature and sunlight? And approximately how long before I will know they took or I can plant them in a new location? (Mayville, N.D.)

A: You are right on in both cases. Just make sure the bleeding heart is done flowering, and you can use either stem or root cuttings. The vining honeysuckle can be propagated via serpentine layering while attached to the plant. Do you have a copy of my "Home Propagation Techniques" circular? If not, give me your address and I'll send a copy to you. As far as temperature and light goes: bright, indirect light -- not direct sunlight -- and room temperatures (70-ish) would do fine. You should see some roots in about six weeks. When the roots look large enough -- about the size of a woman's fist -- they should be able to support the new plant out of their protected environment provided some extended TLC was carried out.


Q: Why doesn't our Dropmore honeysuckle bloom? (Fargo, N.D.)

A: Might be not enough light or too much fertilizer that is high in nitrogen.


Q: I'm never sure what annuals should be deadheaded. I know petunias should be. What about million Bells, stock, geraniums? (E-mail reference)

A: Right now, I cannot think of any that wouldn't benefit from being deadheaded (removing the flowers by pinching back). Certainly something like Alyssum wouldn't be, or any other plant with a similar flower structure.


Q: Last summer, during the hot, humid weather we had, a lot of my annuals (such as impatiens, dahlias, Amaranthus and delphiniums) seemed to turn brown, dried up and eventually died off. They were all planted on the east side. I have grown them there for many years and this is the first time such a thing ever happened. The ones that were more shaded from a neighbor's tree were not affected as severely. It almost looked like spider mites, but I could find no evidence of them. Could it have been rust? I have never seen rust on my plants before, so I would not know if it is that for sure. I use these same plants along the whole east side of my house, as they always did so well. (E-mail reference)

A: First of all, the plants you listed are not all annuals; secondly, it is impossible to tell you what could have killed them off with the information available to me. It is very unlikely that there was a pathogenic organism that attacked all of those plants at the same time. I would suspect herbicide drift or a soil sterilant causing this mischief with your plants. Try a soil test before planting this year to see if the nutrient balance is ok or not. If it turns out to be all right, then I suspect something of the latter to be the problem.


Q: After about a bizillion years of wanting one, I finally received a shamrock plant for St. Patrick's Day. As the pot it is in is really very full, I think I should replant it soon. Can I keep it as a houseplant or does it have to be planted outside? If outside, should I plant it in the shade? Sun? Partial sun? Any advice you can give me will be greatly appreciated. (E-mail reference)

A: Wow! Think of all the history you have seen over all those years! You want to keep this as a houseplant, but you must understand that it goes through a rest or dormant period after blooming. I assume yours is in bloom right now, so I would allow it to complete this normal cycle, then as it declines, back off with the watering until the plant dies down completely. Then remove the tubers from the present pot and place in a 6-inch container and keep moist, not soaked. Be sure at least 1/2 inch of soil covers the tubers, and that there are no more than six tubers per container. As new growth begins, increase the watering and fertilize at least monthly with a dilute solution of houseplant fertilizer such as Schultz's or a similar product. Give the plant plenty of bright indirect light, along with some diffused morning sunlight if possible, and you should be able to enjoy it for another bizillion years or so!


Q: Every year I start a number of perennials and annuals. However, I still don't know what an "untrue" leaf looks like. Do all plants have these? Sometimes my seedlings get a little spindly. Can all varieties be stem planted up to the true leaves (assuming I find out the difference)? (Maddock, N.D)

A: The untrue leaves you are referring to are known as the seed leaves, or cotyledons. Dicots have two; monocots have one. They are always the first leaves to emerge, and assuming there is enough light energy reaching these leaves, new growth takes place and the first "true leaves" appear. Yes, you can plant them up to, but do not bury, the first true leaves. The spindly character of your seedlings can be prevented in the following manner: Replace the fluorescent bulbs every year, and keep them about 10 to 12 inches above the seedlings. Lower the temperature at night by about 5 to 7 degrees, assuming you are running daytime temps at 70-72. Don't fertilize beyond what is absolutely necessary. Many potting soil or seed starting mixes already have a trace of fertilizer mixed in them, so no additional is needed for some time.


Q: I am wondering if the berrys on the flowering crab are harmful to humans, birds or animals. (E-mail reference)

A: No! Some are tastier than others, but none are harmful unless a pesticide residue remains, and that depends on the pesticide used.


Q: Can you tell me where I may purchase dropmore honeysuckle? I bought one about four years ago and haven't seen any since. It grew wonderfully here in our severe climate. (Amidon, N.D.)

A: You might try garden centers or nurseries in Williston or Dickinson. Someone should have this popular plant for sale. It adapts so well to our region.


Q: We have tried for 10 years to get something to grow on my husband's grave with very little success. It lies under a large pine tree and the soil is poor , rocky and thin. Little sunlight reaches the site. There is no water available at the cemetery. I would like to try Silver archangel. (Nay-tah-waush , Minn.)

A: I assume that what you mean by silver archangel is the Galeobdolon argentatum (aka Lamiastrum galeobdolon Variegatum). If anything will make it, this plant should. I have seen it growing in what I would consider impossible conditions.


Q: What pre-emergence chemical can I use in my perennial flower garden, and how often do I need to apply the chemical? (New England, N.D.)

A: I would suggest Preen as a general recommendation. Be sure to follow label directions for timing and rate. 


Q: My perennial bed needs to be redone. When can I move plants most successfully? I am aware September is best for peonies, iris and day lilies, but what about phlox, tiger lilies, etc.? Any help would be more appreciated. (E-mail reference, Iowa)

A: September after a good frost would be a good time to move just about any herbaceous perennial. The old rule of thumb says to move spring blooming plants in the fall and fall blooming plants in the spring. That works, but so does just carefully moving them in the fall. Be sure to water in completely, and don't let them go into the winter in a dry, unprotected state. Put something around them to help catch snow to act as insulation, or simply add it yourself.


Q: I've started getting my flower gardens ready for winter and have a few questions regarding cutting back certain plants: I have a hydrangea that the recent frost does not seem to have affected much and still is somewhat green. Should I cut this back before it dies out completed? How far back should I cut it? Should other perennial plants that the frost has not yet killed and are still very green be cut back or should I wait until the frost has killed them? I have always saved geraniums year after year by pulling them up, drying them out, putting them in a brown paper bag, hanging them in my basement and planting them in March. This has always worked good; however, this year we were gone during the time we got the frost and they look pretty sick. Do you think saving them over winter is worth the effort or has the frost killed them entirely? The reason I like to cut the plants back in the fall is I have a problem with slugs, so I don't like to leave anything for them to hibernate under. (Jamestown, N.D.)

A: All good questions: You can cut the hydrangea back after the foliage has been blackened, made limp or fried by the frosts. Cut back to about 6 to 8-inch stubs. Generally the advice is to allow perennial foliage to remain to collect snow; if slugs are a major problem, then clean up of all debris is called for and shouldn't negatively affect hardy perennials that have been planted for more than a year. Give the geraniums a chance. Cut back any stems that are obviously damaged by frost; throw out any plants that seem to be totally affected. Check them frequently through the winter months to be sure none are rotting, disposing of any that are. So much depends on microclimate in something like this. While the official temperatures might have been at the lethal level, it may not have reached that point at your particular site.


Q: Would you be able to maybe tell me the name of the purple spiky flowers in the flower garden right north of the IACC building at NDSU? The plants are medium sized and the flower spikes are about 4-6 inches tall. They were full of some type of butterflies. (Fargo, N.D.)

A: Those butterfly-attracting flowers are annuals known as Salvia farinacea, or mealy cup sage. They are as easy as sin to grow and virtually disease free, so plan on getting some next spring and enjoy!


Q: Can you tell me the correct name of the enclosed vine that grows up in my lilac bushes every year? It is very fast growing and would work really well for someone with a trellis. Also, in the past I had a snowball bush that seemed to get infested with aphids all the time. I sent for some green leaf insects. When the eggs started hatching I placed them on the bush and it took care of the aphids. I am a bird watcher and was afraid to hurt the birds if I used chemicals to spray the aphids. (Faulkton, S.D.)

A: You are blessed with the vigorous vine Clematis tangutica. The beautiful bell-shaped flowers are only surpassed by the numerous feathery seed-heads. It has probably escaped from the wild and found a suitable home amongst your lilacs. I encourage you to attempt to move it to a new location after everything goes dormant. Any clematis is too beautiful to kill off.


Q: I have two clumps of lythrum that I would like to divide. Would it be okay to do this in the fall or would spring be better? (Williston, N.D.)

A: Lythrum can tolerate either time. I prefer fall, as the root system has a chance to settle in before top growth begins.


Q: Tordon was put on a tree stump to kill the tree. After the kill some tree grinders ground the stump up but didn't clean it up. This is an older lady's tree, and her grandson was here this spring. To be helpful he worked the ground tree stump into her flower bed. She planted annuals twice this spring and both times the flowers died. What can they do to make this a useable flowerbed again? Do you suggest digging out the old dirt and filling in with new? How deep would you need to go? On ground where Tordon was applied, how long before anything can be grown again? They also used Tordon to kill their caraganas and would like to plant grass where the caraganas were. (Stanley, N.D.)

A: Tordon (picloran) has long residual times that can stretch into years. I really cannot give you a time line. Two options exist: Remove the soil as you suggested, going down 4 to 6 inches and replacing with new soil. The question is, where will you dump the contaminated soil? Be sure to think that through before taking action. The second option: add activated charcoal to the affected soil. This will help to absorb the Tordon. Tell her to try planting the grass seed in just a small part of the treated area to see if it germinates and lives. If it does, then it is safe to proceed.


Q: I have a large flower garden that I want to transplant to a different part of my yard. There are many different flowers ranging from daylilies to tulips, columbines to irises, plus many more. When is the best time of year to tackle this project and do you have any suggestions to make it more successful? I also want to move my raspberry patch and was wondering when I should do this and which plants should I choose to move. Some new plants came up this spring that are now 3 feet or more tall, and there are also plants that just came up within the last month or so. When is the best time to prune out old plants? My 9-month-old daughter loves to be outside, but with all the rain lately, mushrooms are starting to grow in the lawn. I try to pick them before letting her play, but I'm afraid she'll still find some and eat them. Are they poisonous? (Woodworth, N.D.)

A: Here are some good rules of thumb to follow when doing any kind of transplanting. Always, unless absolutely necessary, transplant when dormant (not actively growing) in either the early spring or fall (after a few hard frosts). Anything that flowers in the spring is better transplanted in the fall; anything that flowers in the fall is better transplanted in the spring; something that flowers in midsummer, it doesn't make any difference. Move as efficiently as possible between digging and transplanting to a new site. I suggest having a bucket of dilute solution of Miracle-Gro handy for holding the transplants until they get to their new site. Always select the newest canes for transplanting. They will tend to be more disease-free. Cut the old canes out as soon as they are finished bearing fruit. Rule: Any mushroom that you cannot identify positively as being edible is considered poisonous! Knock them out with a golf club or mow them off before your daughter gets to them.


Q: We have a large (18-inch) beautiful lichen growing on a dead tree stump which has been cut off at the ground. It is creamy white in the shape of a rose. We would like to know the best way to remove and preserve this specimen. (E-mail reference, LaMoure, N.D.)

A: I stand to be corrected, but I think the best way to do that is to cut if off as a slab of wood, with the lichen intact, of course.


Q: I have enclosed a sample of redwood bedding that I would like to put down in my flower bed. Is it okay to use? Also, I have a mango and I understand that the inside pit can be planted. What do I need to do with the pit to get it to grow? (Carrington, N.D.)

A: Yes, the bedding looks great! Use it. The mango pit needs to be planted in a 4-inch pot, burying the pointed end and leaving the last one-fourth of it exposed. Keep at room temperature and keep moist. Growth should be noted in four to six weeks or sooner.


Q: I would like to plant a perennial flower garden on the north side of a farm building. I would like to plant a hedge in the back of the perennials to provide a background for the flowers and to add some height. Will the roots from the hedge interfere with the flowers? I would like to plant a dwarf burning bush, which should grow to 4 to 6 feet tall and is advertised as good for zones 3 to 8. (Spiritwood N.D.)

A: Your idea is carried out all the time with minimal problems from the hedge roots, especially the Euonymus you will be using. Go for it!


Q: I have two beautiful fuscia baskets and need to know proper care: fertilize or not, water heavily or not? Also, can I attempt to overwinter them and how? ( Fargo, N.D.)

A: Fuchsias need water daily and fertilization every two weeks or so to look their best. They make poor candidates for overwintering, unless you are planning to overwinter yourself along with the plant, in someplace like Florida! The dry air from the heating system takes its toll on them.


Q: I noticed that several of my favorite Monardas have blackish/brown areas on the leaves and those leaves are dying. What is this and what do I need to do to get rid of it? I would hate to lose these plants. Also, I was reading in an NDSU brochure that the herbicide Confront is very effective against clover and other broadleaf weeds. I have never seen this product in the stores. Is it available to home-owners? The last few years I have had very few tomatoes due to leaf diseases that totally kill the plants. I want to control it this year and would like to know what product I should buy and when should I start applying it. ( Barney, N.D.)

A: It sounds like a fungal disease on your Monardas, but I don't know what disease without examination. Bordeaux mixture is a good broad-spectrum fungicide. Give it a try and see if you get any control. Confront is not available to homeowners, only to lawn care applicators. I suggest going for the AAS winner tomato varieties that are more disease resistant and plant them in a different location. Also, try to avoid water splash on the foliage; use a drip irrigation system if possible. You can use a fungicide containing chlorothalonil, repeating every seven to 10 days until harvest.


Q: How can I get information on rununculas? (E-mail reference)

A: Ranunculus asiaticus, or Persian buttercup, is hardy in zones 8 to 10; elsewhere grow it in pots. Plant in damp, light, well-drained, compost-rich soil in the autumn, or until the soil freezes. Bulbs will rot if planted in hot weather. Grow in full sun, keep cool at night. Flowers come on in early spring in a variety of bright colors - from red to white, with orange and pink in between. Some are single flowers, but most are bred now for double or semi-double flower show.


Q: I have a 3-year-old Meadowlark forsythia that is blooming very nicely at the moment. I am wondering about its growth habit and how I should prune it. It is about 3 to 4 feet tall now. does this shrub sucker or does the growth emerge from the common trunk? I have plenty of space and would be able to accommodate a very large plant. What is the best way to prune to encourage growth in width as well as height? (E-mail reference, Bismarck, N.D.)

A: The Meadowlark forsythia can be pruned right after it is finished blooming. I suggest cutting out the largest two or three canes, right back to the base of the plant. This will get to be a large, spreading shrub 6 to 7 feet tall and about 4 feet wide. Don't worry, it will fill in a pretty big space.


Q: Here is the scenario: north shore of a lake, house built on a bluff, erosion under deck necessitating stone riprap. The plain rocks look rather utilitarian. Any ideas what to plant that will in time soften this? Riprap total is about 70 feet long and maybe 12 feet wide. (E-mail reference, Erhard, Minn.)

A: Yep, you bet! Daylilies. You can't beat them for "softening" something like this. Of course, the more the site is shaded, the fewer flowers, but they will grow and gradually spread, helping to hold your riprap together.


Q: One of your readers asked about the beautiful Hadspen blood astrantia. I had been searching local nurseries here in Oregon ever since I saw it featured in Better Homes and Gardens about two years ago. Last week I went to a nursery right by my home and found that they have several. It is Gossler Farms Nursery, 1200 Weaver Road, Springfield OR 97478, (541) 746-6611. They try to carry plants that are not usually stocked in other nurseries. (E-mail reference, Springfield, Ore.)

A: Thank you for that information! Readers who might be interested in that plant will be delighted to know where they can get it this spring.


Q: I am sending a picture of a morning glory that I planted around a stump. It looked very healthy, but it never bloomed. Another lady in town also has a morning glory that didn’t bloom. What are we doing wrong? (Jamestown, N.D.)

A: Judging from the vigor of the vine and its location, I would guess that it is getting too much nitrogen, giving it all vegetative and no flowering growth.


Q: I have a space in my yard, about 150 square feet, which I plan to make into a perennial flower garden. My concern is that I do not have enough room in my home to start the seeds early. Could you please give me some advice as to when and how to plant? I would like to get started early enough so I can enjoy the blossoms for a while. (Langford, S.D.)

A: Important to keep in mind is the fact that some seeds need light to germinate, while others don't. That little detail is often the difference between success and failure. The source for that information is usually on the seed packet or in the catalog where you made your purchase.


Q: I'm writing from southern California (near the coast), a long way in both distance and climate from the North Dakota; nevertheless, an Internet search using the word "lisianthus" revealed your Web site. Two other sites were selling cut flowers. So ... I thought that I would write and see what you know about the plant. That, by the way, is guaranteed to be more than I know. Believe me.

I planted lisianthus in patio containers last year and they've remained green. Are they perennials in a Mediterranean climate? Will they bloom again, or should I just be thankful that they're still there? (Fountain Valley, Calif., e-mail)

A: We grew lisianthus (Eustoma) as a trial cut-flower crop in our plots for a couple of years. They are definitely warm-season flowering plants, with some species being annual, biennial and perennial (in your zone). The plants will only rarely look good beyond the first year, so rather than waste your life waiting for the possibility of a repeat performance, get another planting under way.

I'm sure you found them to be excellent cut flowers, as we did. Our stems were too short, though, for the local florist trade. They all wanted your long-stemmed California beauties! When arranged in a vase containing water, this flower's buds will open and give the viewer an extended show!


Q: Are you familiar with the perennial Hadspen blood astrantia? If so can it be grown here and where can it be purchased? (Fargo, N.D.)

A: I'm unfamiliar with the perennial and four of my plant books know nothing about it either. Perhaps one of our readers will know about it.


Q: What kind of results would I get using seed from hybrid flowers? (Dazey, N.D.)

A: Mixed: a range of colors, sizes and shapes.


Q: I raised some bird house gourds this year and believe it or not, there are some 12-inch gourds coming! Now I don't know what to do next! Should they be left on the vine until it freezes? Would I hang them in a cool, dry place to cure and how long will that take? (Fessenden, N.D., e-mail)

A: Yes, allow them to stay on the vine until our first frost. Then harvest and drill a small hole in the blossom end to allow air in. Hang in a cool, dry location until you hear the seed inside rattle. Then you can cut, paint or do whatever to your heart's content!


Q: I was watching a home and garden channel on TV and they were showing a garden in Canada. There was a very pretty plant they referred to several times as a "gas plant." It had flowers and is a perennial. I can't find any plant by that name in my books. Can you please help me out? (Garrison, N.D.)

A: Gladly. The Dictamnus albus is a hardy perennial that once planted doesn't like to be moved. Enjoy!


Q: I have started seedlings indoors, and now that they are up--under a fluorescent light and as green as can be--how do I minimize or strengthen the lanky stem? I have a fan available to circulate air, but I fear the air may be too cool, as I see a bit of brown on a couple little leaves (they just have two leaves now). How often shall I have the fan on? (Williston, N.D., e-mail)

A: If the fan is moving the ambient air that is normally in the room for humans, the air should not be too cold. Just don't make it too strong! Lower the temperature somewhat, or expose them to stronger light, by moving the light fixture closer to the plants. Moving them to a sunny window would also help. Don't be afraid to pinch them back either.


Q: We have an area that we would like to plant solid with perennials that are low maintenance. The area is located on the east side of the house so it gets full sunlight for part of the day, and then is shaded the rest of the day. What do you suggest? (Williston, N.D., e-mail)

A: Some of my favorites include the following: Bergenia cordifolia--makes a good border and is valued as much for the heart-shaped leaves as the flowers that range in color from white to a rose color. Campanula cochleariifolia (creeping bellflower)--another low grower that has beautiful blue flowers. Arabis spp. (also known as rockcress)--another good one for edging or as a ground cover; used frequently in rock gardens. Dicentra spectablis (bleeding heart)--one of my favorites, and it does well on east exposures. I've seen them grow to 4 feet by 4 feet in well-tended gardens; in a minimum maintenance garden, probably cut those dimensions in half. Aquilegia spp. (columbine)--a lot of cultivars to choose from. Will self-seed somewhat. Get to about 12 to 18 inches in height. Astilbe simplicfoliatry and find the Sprite cultivar, as it was the Perennial Plant Association's 1994 plant of the year. It has nice shell-pink flowers. Hemerocallis spp. (daylilies)--will grow just about anywhere. Give them space to spread and place them toward the back of the garden.


Q: Last fall I took a slip from an impatiens flower, rooted it and it grew! My mother's plants always grew long and spindly, so about December I pinched out the heart. It is still alive with five leaves (two dropped) and looks healthy. It never grew any more shoots or leaves since I pinched the heart. I had planned to take slips this spring, but there aren't any. What should I have done? (Jamestown, N.D.)

A: The best thing you could have done was to root the slip that you cut off from this plant. Next, use only florescent lights or genuine Gro Lights for plants (they are more expensive, but have a better light spectrum). Be sure the lights are close enough to the plant to allow for non-spindly or stretched growth.


Q: Can a 20-year-old lilac be cut way down to improve it? If so, when is the best time to do this? I have the same questions regarding a spirea. And finally, I have a perennial flower bed taken over with quack grass and other weeds. Is there a chemical control or should I just dig the bulbs (mostly iris) and other flowers, use roundup and then replant? When would be the best time of the year to do this? (Jamestown, N.D., e-mail)

A: Lilacs and spirea can be cut back to the ground, but it should be done when they are still dormant in the late winter or early spring. Doing so now may weaken the plants too much to generate a decent regrowth. I wish there was a magic chemical that would take out only quackgrass! I have had to do it several times with my flower beds. Dig your flowers up and get every last bit of the quack that you can, either mechanically or by using Roundup.


Q: My mom has a lot of grass in one of her flower beds, which just has tulips and irises in it. Is it safe to spray Roundup or is it going to kill the flowers? Also, she has grass in her raspberry patch, so is it safe to spray Roundup in there or will it kill the raspberry plants? She read somewhere that it was a good idea to put down a lot of straw in with raspberry plants because the straw will choke out the grass. Is that true? (Battle View, N.D., e-mail)

A: Roundup is safe as long as it does not get sprayed directly on the green foliage of ornamental or edible plants. It becomes deactivated as soon as it hits the soil. Straw or grass clippings will help smother weed growth among raspberries.


Q: I have an American bittersweet vine. Why doesn't it produce fruit like the information says it will? (Minot, N.D., e-mail)

A: You received the male instead of the female plant. This is primarily a dioecious species (separate sexes). You should have ordered a female clone as well. If you were promised a fruitbearing plant, you should try to get a refund from the nursery. Ideally, the plants are sold in pairs like holly, one female and one male.


Q: I recently planted creeping phlox. After a few days it began to turn brown and yellow. When I asked at the nursery where I purchased it, I was told that I should apply iron. I did this, and it is rapidly dying. Most of the 20 plants that I put out are three-quarters brown now, plus the mulch that I had around them has changed color. I followed the package directions on the iron. Is there any hope of saving these plants? (Windsor, Ill., e-mail)

A: It sounds as though the local nursery gave you a quick-fix answer without really diagnosing the problem. It could be that your phlox was going through transplant shock. Or it could be that you were given woodland phlox--a shade-loving species--and you planted it in the sunny location. Generally, to get plants off to a good start we usually recommend Miracle-Gro for nonorganic gardeners and fish emulsion for the organic ones. Based on what you are telling me, I suggest that you get back in touch with your nursery and see if they will split the cost of replacement with you. Creeping phlox is generally an easy plant to grow and well worth the effort. I have had some growing in my yard for more than 10 years.


Q: I have a trumpeter vine or butterfly vine. It grows slowly and I can not get it to blossom. It is 3 years old. What am I doing wrong with it? Also, I have not repotted my Christmas cactus for five years, and I am wondering if it is time. (Morris, Minn., e-mail)

A: I suspect you are being too good to your vine. Try root pruning it a little to stimulate flower production. Simply drive a straight-edge spade into the soil a few feet away from the vine to sever some of the roots. Avoid fertilizing at all. If it still fails to flower next year, then it is likely in too shady a location. Concerning your question on the Christmas cactus, if it has been five years since the last repotting, I would say that repotting it in the next nominal-size container would be a good idea. Summer it outdoors--not in direct sunlight--and it should produce an abundance of blooms for you this winter.


Q: Two years ago a friend gave me seed she said was Queen Anne's lace. It is now flowering, but the flowers do not look as full as garden book pictures of Queen Anne's lace. Also, it is at least 6 feet tall and the stems have purple blotches. There is no "hair" in the foliage as books say Queen Anne's lace has. My plants are pretty, but the flowers aren't what I wanted, and the worst of it is that I think it’s poison hemlock. Even worse than that is I scattered the leftover seeds in the windbreak as a wildflower when I planted the eight plants that I have in the flower garden. So far I haven't noticed any except the eight but I'm worried about it. How do I get rid of this? I have to cut the flowers off pronto so it won't seed. Should I chop it all of the way down and then use Roundup on what's left? Should we burn the foliage? Everything I've read about poison hemlock says you have to be careful in how you handle it. (Carrington, N.D., e-mail)

A: You are very wise to be cautious with wild members of the parsley family because some are poisonous, such as poison hemlock and water hemlock, while others are not. Poison hemlock (Conium maculatum) can be easily confused for Queen Anne's Lace--except the hemlock stem is hollow, and when crushed, it has an unpleasant odor; whereas, the Queen Anne's Lace has a carrot-like smell. As you correctly pointed out, the poison hemlock is also taller--getting to 8 feet in height with leaves being finely divided and up to 1 foot long. I suggest using Roundup on all eight plants and any that you see coming up in the future. Once the plant is dead, dig out the remains and burn it to be on the safe side. I don't want you to walk in the steps of Socrates by mistake!


Q: I was wondering if you new any way to get a mum to bloom earlier than frost. I have about 20 plants by my garage, and they have been there for three years. The first year they boomed in August, but the last two years they did not bloom until October. What can I do? (Morris, Minn., e-mail)

A: My best suggestion is to move them to a sunnier location, where they can get sun most of the day. Mums move easily, so you don't have to wait for a particular time in the season to carry out the task. Don't over-water or over-fertilize. If they still flower too late, then I'd suggest dumping them and making a selection from either NDSU’s or the University of Minnesota’s recommended list.


Q: I have a perennial bed on the north side of a low building that gets full sun from about 3 p.m. on but stays quite wet. What perennials can I plant in such a location? Some daylilies I planted there are doing OK, but I think they need more sun for good bloom. Also, I love mums but have poor results in getting them to come back. Any suggestions? (Bismarck, N.D., e-mail)

A: The daylilies should hang in there for you, as they are quite shade tolerant. Similar selections include lily of the valley, hostas and astilbe. You are probably better off treating mums as annuals. In other words, set low expectations for their perennial character and you won't be disappointed.


Q: I have been trying to start slips of Engleman ivy, the creeping vine, but I have been unsuccessful. Can you tell me how to do it? (Fargo, N.D.)

A: The ivy, for your likely conditions, will root best from hardwood cuttings taken in early spring before leaf-out.


Q: We have two beautiful spirea that have always been covered with white blossoms every spring, except the last two years. Could this lack of flowers be caused by my pruning the new growth in June? (Neche, N.D.)

A: Yes, absolutely! If the spirea need pruning, it should be done right after flowering is over. You learned a lesson I’m sure will never be forgotten!


Q: Can you tell me what the enclosed sample is? It is a perennial flower that someone gave me, but I’m not sure what it is called. (Carrington, N.D.)

A: The plant sample you sent was Anaphalis triplinervis, better known as Pearly Everlasting. They typically get 12 to 18 inches tall, although I’ve seen them taller. ‘Summer Snow’ is a compact cultivar, getting to no more than 10 inches tall. This one makes a neat compact border of silver gray foliage. A closely related species, A. margaritacea, gets to 2 feet tall and tends to be more invasive but it appears to survive drought periods better.


Q: Can I get a Trumpet vine to grow up the side of my house, which is vinyl sided, with not much support? I would have a trellis but not as tall as I would like the vine to grow. I have one growing up my yard light pole but I see no tendrils. How do they hang on? If this type of vine won't work, will another do the job? (E-mail reference, Glyndon, Minn.)

A: It will not work. Try a clematis on your trellis. You'll be much happier! The trumpet vine (Campsis radicans) is a rampant, clinging, strangling, take-over-everything vine. Don't get me wrong, I like this vine, but you need to keep it at a spot where you can reach it to keep it pruned. It supports itself with root-like holdfasts which could cause a problem with your vinyl siding.


Q: I have planted gladiolus bulbs in my garden for years and I always dig them up in the fall. I always had a beautiful variety of colors until this year, when they were mostly yellow and white. How is this possible? Also, after my delphiniums finished blooming I cut them back. Now we have had so much rain that they have grown about 18 inches and are forming buds. If I trim them back again this fall will they flower next year? (Garrison, N.D.)

A: Your first question stumps me -- I have no idea why they would change colors! Mutations are possible, but not on the wholesale basis you describe. Yes, the Delphiniums will flower again next year for you. They often get two blooming periods in during a growing season if the summer is long enough.


Q: Enclosed is a picture of a Bougainvillea that I brought back from Mexico three summers ago. It goes dormant in the winter but gets lots of bushy leaves in the summer. My problem is it has never bloomed and I am wondering if it ever will! (Fargo, N.D.)

A: Bougainvillea need all the direct sunlight our northern climate can give them. Yours is certainly healthy and beautiful, and should eventually bloom if it can get enough light. Poinsettias originated from Mexico also, and it was discovered that they need short days in order to flower. Perhaps the Bougainvillea is the same way -- flowering influenced by day length -- either long or short - I honestly don’t know. Perhaps on your next visit to Mexico you can talk to a horticulturist and see if they can give you an answer. They bloomed for us when we were living in Saudi Arabia, but I’ve never studied or seen studies on what it takes to get them blooming. For now, I’ll still suggest "as much direct sun as we get."


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