June 28, 2001

Hortiscope

Ronald C. Smith, Horticulturist
NDSU Extension Service

Q: We are planting a small black hills spruce. My question is, should we fertilize it when we plant? I read someplace we shouldn't do this, especially the first year. A friend said maybe we should use some gro-stakes fertilizer that are l0-10-10. Should we? (Grand Forks, N.D.)

A: Definitely do not fertilize now, and especially never fertilize with the fertilizer spikes. They concentrate the fertilizer in certain areas and have not proven to be superior in any way for fertilization of trees. It is simply a marketing gimmick, I'm sorry to say, that gets consumers to spend money for fertilizer that is usually not needed. This fertilizer is the most expensive form to purchase and does very little good, if any.

Q: We would like to know how to start some maple trees from seed. We have a beautiful old maple tree in our farmyard which we guess is a Norway maple and seems to be well adapted to this area. We have gathered a number of seeds this spring and are wondering if it is possible to start some seedlings and what would be the best way to do this. (Centerville, S.D.)

A: If it is Norway maple, you need to stratify the seed in moist peat for 90 to 120 days at about 41 degrees F. This can be done in the vegetable crisper in the refrigerator. This species can also be rooted in mid-June by taking semi-softwood cuttings, dipping them in a rooting hormone and placing them under an intermittent mist system with bottom heat.

Q: I bought a schefflera and I must have overwatered (my personal bad habit) the plant and now almost all the leaves have fallen off, but the three "trunks" or stems are still very strong, not bent or dying. How do I get new leaves to grow? (E-mail reference)

A: You are in a lot of company when it comes to that bad habit! Try cutting it back to where the lowest leaf was attached and placing it in strong indirect light. Water moderately and give it a shot of fertilizer once a month. If at the end of two to three months nothing has broken bud, forget it and start over.

Q: For Mother's Day, my son gave me a beautiful hydrangea plant with gorgeous lavender flowers. I live in an apartment and am not able to plant it outside. It is still blooming and doing fine. Any suggestions for keeping it indoors? (E-mail reference)

A: If you can, summer it outdoors on a patio or porch. If not, try to keep it evenly moist. Use rainwater or deionized water if your tapwater is hard. Mist the foliage often. Once it is done flowering, repot and overwinter in a frost-free room, watering sparingly. Around the first of February move it to a brighter location, increase watering and give it a shot of fertilizer.

Q: I would like to know if mothballs really keep cats and dogs out of gardens. If so, will it keep the cats out of the kids’ sandbox? (E-mail reference)

A: It usually works to keep the cats out of the flower beds, but I don't recommend it for children's sandboxes for obvious reasons. I suggest simply covering the box when the kids are not using it.

Q: Attached is a picture of an orange jelly-like substance that is growing on a juniper bush. Could you please identify and suggest control measures? (Stanley, N.D.)

A: A good photo of the cedar-apple rust gall development. It seldom causes great harm to the juniper but is devastating to the alternate hosts--anything in the Rosaceae family, like apples, pears, hawthorn and juneberry. I suggest that all such galls be harvested as soon as possible and destroyed.

Q: The first bud on my iris would open nice, but the second ones would then be "mushy." Our weather has been really good up here so I doubt excess moisture would be the cause. Any suggestions? ( Mohall, N.D.)

A: Possibly thrips. They are known to attack iris flower buds. Or it could simply be botrytis, which is a common blossom blight. It doesn't take much for this to get started; cool nights leading to heavy dew that sits for hours on secondary flower buds could cause the problem. I'd put my money on that without seeing anything up close and personal. Control is by removal of the infected parts, and spraying with captan, chlorothalonil, or maneb.

Q: This spring we planted grass on our 2-acre lot. Moisture wasn't timely, so we watered as best we could. Shortly after we planted we also had high winds, which blew a lot of the seed away (as well as a little topsoil). On the north side of the lot, the grass is coming along quite well.

On the rest of the lot, growth is spotty. In some areas the quackgrass and other weeds have taken hold. In a few spots the ground is bare of all growth. My husband put hours into soil preparation and seeding, so the thought of burning it down and starting over does not appeal to me at all. What is the best method to "fix" a newly planted lawn problems on a yard of this size? (Bismarck, N.D.)

A: Best approach is to get a power rake or lawn dethatcher and run it over the bare areas to scarify the soil. Broadcast more seed, and topdress with a wood-fiber mulch that will help hold it in place and extend the effects of rain or irrigation. Weeds will be a problem, but they can be beaten with persistence. Once you have enough grass to mow, you can then attack the weeds with the appropriate herbicide. Hang in there! A year from now this will be a memory hardly worth recalling.

Q: My Montmorency cherries bloomed erratically this year. On one tree with three trunks one trunk has delayed blooming and leaf production. It is not completely dead but very far behind the rest of the tree. A large plum tree 20 feet away has a problem consisting of tiny green tubes growing on the bottoms of the leaves. The other cherry tree has several branches that are not blooming also. Can I save them, and how? ( Bismarck, N.D.)

A: It doesn't sound too hopeful. The one tree with the delayed blooming is a sign of possible partial death of some of the feeder roots or a canker developing on the tree. The mere lack of blooming does not signify necessarily anything more than the buds possibly being zapped by the cold this past winter. The one with the best hope of surviving is the one with the green tubes on the bottom of the leaves. That is simply a gall that is cosmetic, not lethal.

Q: We live in southeastern Massachusetts and the deer population is taking over. It was a fairly rough winter this past year and the deer feasted on our plants. A large rhododendron was almost denuded, with only a few leaves and blossoms left on a couple of branches. If I cut it back almost to the ground, will it grow back? If so, what should I do to help it along? What is the best technique for keeping the deer away from the plants? Fencing the yard is not an option.

They cleaned off a stand of 14 arborvitae trees up to about 5 feet, leaving a tuft of healthy branches at the top. What can we do besides cutting them down or digging them out? Will they grow back, and if so, how long would it take for them to fill in again? (E-mail reference, Massachusetts)

A: You definitely have a problem! Go ahead and cut the rhodys back, water and fertilize with aluminum sulfate. If they are going to make it, something should be evident soon. I'm afraid I can't say the same thing about the arborvitae. They are simply too far gone. There are many deer repellant products on the market, and all of them work, up to a point. Out here we try human hair tied to branches, scented soap, dried blood, predator urine and repellent sprays, and like I said, they all work, up to a point.

Q: We just cut down one of my big Red Canadian trees. It was full of black knot. Could you suggest a tree to put in its place? I would like something that turns red in the fall but want something that is hardy to the area and not susceptible to black knot. We also lost a tree to the deer. They rubbed all the bark off of it and it died. This was a flowering crab. Any ideas what I could plant in its place? (Tappen, N.D.)

A: I would suggest planting a hawthorn (spines and all) in both locations. That would keep the deer away and provide food for the small wildlife in the area. They have an attractive red/gold fall color as well.

Q: I have a hybrid poplar I planted as a bare root plant six years ago. It grew rapidly and very full each year. This year there are hardy any leaves. It looks dead. There is green under the bark, however. Did it go dormant this year? Should I cut it down and start over? Or will it come back next year? It is about 20 feet tall. (Rapid City, S.D.)

A: It doesn't sound too good to have a poplar not in leaf at this time of year. I suspect it could be the roots have caved in, or the buds were killed off by the winter. If you don't have any foliage emergence turn it into firewood.

Q: We got an indoor azalea plant as a gift but no directions on how to take care of it. It has started to lose its leaves and the buds have turned brown. It’s starting new growth in some sections. I have it in a window with some sun during the day, but was wondering should I put it under a plant light instead. Most of the tiny branches seem dry, but I have been fertilizing with miracid for home use. I was told to re-pot to a sturdy pot, which we did. What else can I do? (E-mail reference)

A: It is rare for indoor azaleas make it beyond the initial blooming stage that the growers have induced. I suggest that you dump it, but, if you don’t wish to do that, to plant it outdoors for the summer in a 50/50 mix of peat moss and sand to see if it recovers. If it does, great--count yourself among the rarely successful!

Q: I absolutely love Hydrangeas and would like to find out to what variations of colors are available. Are there certain hybrids that have certain colors? (E-mail reference)

A: The colors are often a result of a dye the florist has put in the water prior to retailing them. True colors can be switched back and forth between pink and blue by using lime for the former, and aluminum sulfate for the latter.

Q: The leaves on my rhubarb have holes eaten through all over and then marks on the stems. Some of the plants are no longer growing new leaves. I've sprayed, which didn't help. I'm afraid this is going to kill my rhubarb. (E-mail reference)

A: It sounds like you have some slug activity. Bug spray will not help. Pick up a slug poison or place some stale beer around in shallow pans to collect them.

Q: I have three flowering plum trees (Prunus autumnalis) that bloomed this spring and now the leaves are curling, drying up and falling off. The leaves seem to have dark spots on them also. I could see no bugs or cankers. Would this problem be fatal to the trees and what can we do about it? (E-mail reference)

A: It sounds like it could be brown rot, a fungus that overwinters in the dried or mummified fruit remaining on the tree. Spray with Benomyl or Captan and pick off all old remaining fruit this fall. Spray next spring before leaf out with lime-sulfur spray to sanitize the tree.

Q: My peonies are finished blooming. Do I cut the dead flowers off now? (E-mail reference, Missouri)

A: Yes, cut them off when they have finished blooming so they don't waste energy making seed.

Q: We have an area in our lawn with a severe infestation of Japanese beetles. We would prefer to use biological controls rather than chemicals, particularly since we have planted a large number of flowers and shrubs in the last two years that will attract butterflies and bees. We are trying to restore our outside environment without harming beneficials. I have ordered some beneficial nematodes to help battle the beetles. However, I am wondering what you can tell me about the effectiveness of milky spore disease, and whether you know of any sources where this can be purchased, since I haven't been able to locate any. Thank you for your assistance! (E-mail reference, Jamestown, N.D.)

A: You don't have Japanese beetles. You have a type of Scarab beetle, called May or June beetles. Fortunately, Japanese beetles cannot survive our winters. Try the "Gardens Alive" catalog. Milky spore disease is listed on page 5. Call them at (812) 537-8650.

Q: We have a weeping birch that the deer broke a small branch off of. The larger branch it was connected to has now dried up almost completely. I am wondering if I can cut it off without losing any more of the tree. This tree is 22 years old and very tall. I am afraid it might all die if I cut any branches off of it. Is there a way to do this without damaging any more of the tree? (Tappen, N.D.)

A: Simply cut back to where another branch exists for best healing. The wound will heal quickly at this time of year. Do not apply any dressings.

Q: I bought a new house in an area that has a lot of clay and the drainage is poor. I have two plants that I am worried about. One is a silverberry that has very small leaves, the other is a maple that also has smaller than normal leaves. The soil is very wet about 18 inches down. Would raising them help? (E-mail reference)

A: Yes. Neither species does well with constantly wet soil. Raising would help but is tricky, so be careful. If there is some way you can install a French drain system around the trees to pull the water away and to a sump area, that would be better. If not, move the trees into a "raised planter" type setting where the water can drain.

Q: I'm having a terrible time germinating tulip seeds. I saved a tulip pod last year, planted the seeds in little flats, and they germinated after a few months at the back of the refrigerator. The tulip seedlings came up, grew into little green threads, and then withered back, seeming to have formed tiny little bulbs. It wasn't damping off disease, and nothing I've tried so far has gotten them to come up again. If you know what the next step is, or what I'm doing wrong, I'd really appreciate some help! (E-mail reference, Canada)

A: You are asking me about something I have never done, so my answers are going to be based on what I think is a logical sequence to follow. If they truly formed little bulbs, then they need a cool period, refrigerator levels, for at least 90 days. Then take them out and plant them in some potting soil where they can get warmth and light. They should sprout again, making foliage but not flowering. This procedure will probably have to be repeated for another season or two before the bulbs reach a "planting" size for the outdoors.

Do you have a gardening or houseplant question? Write to Hortiscope, Box 5051, NDSU Extension Service, Fargo, ND 58105 or e-mail to Ron Smith at ronsmith@ndsuext.nodak.edu. Note to e-mail correspondents: please identify your location (city and state) for most accurate recommendations.

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Source: Ron Smith, (701) 231-8161, ronsmith@ndsuext.nodak.edu
Editor: Gary Moran, (701) 231-7865, gmoran@ndsuext.nodak.edu