October 30, 2003

Hortiscope

Ronald C. Smith, Horticulturist
NDSU Extension Service

Q: I would like to ask you two simple questions about a jade plant. How often should I water it and what kind of light does it like? Sometimes a leaf gets a little shriveled and falls off. What's wrong? (E-mail reference)

A: Give jade as much light as you can. That way it will not get soft and floppy. Water it when the upper third of the soil is dry. With consistent care, it will stop dropping leaves.

Q: I have a 17-year-old apple tree. The bark is coming off in several places and the trunk is starting to split. I would love to save this tree so I would greatly appreciate any help you can give me. (E-mail reference)

A: Wrap the tree this fall before freeze up with Kraft paper. This protects the tree from a freeze thaw cycle in the plant tissue during the sunny but cold days of winter. Be sure to remove the wrapping next spring as new growth is beginning to unfold. If you cannot locate the paper wrap (best in my opinion), then find some coiled plastic that would do the job.

Q: I have started a tree farm and one tree species I have planted is aspen. I ordered trees from Baileys and Lawyers ranging in size from 1 to 2 1/2 feet. I also have some 5-foot trees. They are all growing well but they have larger leaves (that do not tremble) than the natives in the Black Hills and they do not get the fall gold color. They turn an ugly brown and drop off. My customers will not buy the tree once I tell them that they may not have the gold color in the fall. Why don’t they get the good fall color this species is known for? (Sturgis, S.D.)

A: Because you were sold something other than the quaking or trembling aspen species. Insist on botanical names from nurseries. Populus tremuloides is the quaking aspen that gets the yellow fall color on the leaves.

Q: I have some clematis vines on a trellis in my yard and wonder if I should cut them back or just let them be. I have read publications that recommend cutting back the vine and covering with mulch. Other publications recommend leaving the vine alone and covering the base with mulch. (Jamestown, N.D.)

A: I guess either way would work but it has been my practice and recommendation to prune back in the spring to encourage new growth. That way you can see what has or has not survived the winter. Be sure to mulch the base generously just prior to freeze up.

Q: I am frustrated and thoroughly dumbfounded with the misfortune I'm having with my uke pear tree. This is the third one that's looking for a gravesite. It must be highly susceptible to disease, such as blight, which I think it has. The tree looked healthy when I bought it from the nursery. I sprayed it five times but the disease must have been too far advanced. Please help if there is any hope for this problem. I'm thinking of a less blight susceptible variety such as Summercrisp. (Harvey, N.D.)

A: Go for it. I've had bad luck with pears too! Summercrisp should fare better.

Q: About three years ago we purchased a restored 1918 farmstead, located 4 miles north of Bucyrus. I need help planning foundation plantings. The only foundation plant is a lilac, growing right next to the foundation. We have planted two poplars and two bushes. (Hettinger, N.D.)

A: You need to lay the part of your property you plan to landscape on graph paper to a 1:10 or 1:20 scale. Then create areas you want to add plants to. The bed shapes should be free flowing and generous in size. Spirea, viburnums lilacs, potentillas, honeysuckle and forsythia are good foundation plantings. Evergreens that can be incorporated into such plantings include many junipers and taxus (yews) on the north side. I would certainly want to intersperse these plantings with ornamental grasses and herbaceous perennials. I encourage you to get rid of the poplar and "purple bush" right next to the house. Better to start over with a clean slate.

Q: I would like to know why my snow on the mountain gets brown leaves. (Oakes, N.D.)

A: This is just a reaction to the high pH and salts in the soil. Often mid summer mowing can prevent leaves from getting brown because it pushes out new growth.

Q: We have two wonderful apple trees that provide us with tons of apples. What is the best way to store them for the winter? I find that they get soft and mushy very quickly.

Also, when do I dig up glad bulbs and how do I store them until next spring? (Jamestown, N.D.)

A: Apples store best at just about freezing and 90 percent humidity. The storage life of apples is also dependent on the variety. Early apples have a short storage life while later apples have a longer storage life. You could have an apple like the Hazen, which is an excellent variety, but has a short storage life. Dig the glads after the first frost that nips the foliage. Dust them with sulfur and store in a dry, cool location.

Q: We have a problem with our potatoes. They were planted in the garden for the second year in a row. They did not come to a full bloom, looked sickly and were treated for fungus. They did look better but did not grow much and quickly dried up before the season was over and before they could mature. Can this fungus be in the soil and infect the next crop? (Beulah, N.D.)

A: Always start with clean, certified seed potatoes, and rotate the planting site with something outside the potato family such as peas, beans, corn, or cabbage. Only plant potatoes in the same site every three to four years.

Q: I have a 35-year-old green ash. All insects seem to like this tree. For the past five years I have been having it injected with an insecticide that kills all the insects. Do yearly injections harm the tree or can I keep doing it indefinitely? I thought that the tree was slow to leaf out this year, but I suppose that it could have had the first buds frosted. (Billings, M.T.)

A: It shouldn’t be a problem as long as the person doing the injections knows what they are doing. You might try a dormant oil spray next year before the tree leafs out. This may solve the problem by killing the insects in their over-wintering stage. The same tree service that does the injection work for you could likely provide this service as well.

Q: My son lives in Minneapolis and he needs advice on how to kill quackgrass. It is starting to come in by his sidewalk and is spreading in the lawn. (Ashley, N.D.)

A: Unfortunately, there is no select way of eliminating quackgrass from turfgrass. In the sidewalk, just about anything can be used, with Roundup being the best choice. In turfgrass, the best approach is to maintain the lawn in a vigorous manner with regular irrigations and fertilizer and mowing at the high end of Kentucky bluegrass range, which is three inches or more.

Q: I would like information on how to get rid of night crawlers in a lawn. (Jamestown, N.D.)

A: Nightcrawlers can cause walking discomfort when their population is high in the spring and fall. There are no approved chemicals for nightcrawler control, although some fertilizers, as well as pesticides (to control weeds, insects and diseases) have been known to have an impact on their populations. Taking good care of your turfgrass will minimize nightcrawler problems. This involves core aerating, power raking and at least two fertilizer applications per year. The fertilizer should be applied in mid-spring and late summer.

Q: I am enclosing a piece of an invasive vine that is all over my flower garden. I can't seem to locate the source of this creepy plant. When I try to dig it out, it keeps going and going, so I end up snipping it off. I thought it might be some sort of willow whose roots seem to crawl and appear everywhere. Is there anything I can do to keep these troublesome invaders out of my garden? (Carrington, N.D.)

A: This appears to be a smartweed (polygonum spp.). It is an annual, so it will die down this fall. Apply Treflan next spring before new growth begins to see if you get any control.

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: Rich Mattern, (701) 231-6136, richard.mattern@ndsu.nodak.edu