NEWS for North Dakotans
Agriculture Communication, North Dakota
State University
7 Morrill Hall, Fargo, ND 58105-5665
October 1, 1998
Hortiscope
Ron Smith, Extension Horticulturist
North Dakota State University
Q: Can you please let me know where I can get an oleander and an angel wing begonia? (Jamestown, N.D.)
A: Oleanders are extremely poisonous plants, and because of that, I do not suggest them as houseplants. They are used outdoors as hedges in the deep South.
For an angel wing begonia, I suggest contacting a local nursery, greenhouse or florist shop. There are several good ones in Jamestown.
Q: Can you tell me what kind of trees these are? (Lisbon, N.D.)
A: Your trees are Amur maples. Good ones for our area.
Q: Can you tell me where I can purchase some oxalis bulbs? (Martin, S.D.)
A: Come to our campus! We have plenty of oxalis growing everywhere, but not the kind you want, I'm sure! Quite frankly, I don't know where you can get these interesting plants from. I only know they show up at retail outlets around St. Patrick's Day. You might check with some local florists and see if they can get any for you.
Q: Could you please tell me how to start a compost pile? Where is the best place, what type of container and is it too late this year? (Warwick, N.D.)
A: I have enclosed an extension publication on composting practices, "Composting Practices" (H-885). You are better off waiting until next spring.
Q: My apple tree leaves have all dried up and the bark is turning black. Enclosed are some leaves for you to examine. What kind of disease does my tree have, and is it still safe to harvest and eat the apples? I have other trees located near this one. Are they in danger also? (Lankin, N.D.)
A: Certainly go ahead and enjoy the apples! What I am seeing mostly on the leaf samples you sent are indications of root problems: a rise in the water table, root rot or a basal canker. With any of these, all you can do is wait for the tree to die.
The other trees are not necessarily in danger unless they are close enough for root grafting to take place. Sometimes trees afflicted like this take years to die, and other times they are history in one growing season.
Q: I have a juniper shrub that is almost 20 years old alongside of our house. I have pruned it before, but it is getting overgrown again. Is now a good time to prune, or should I wait until next spring? (Oakes, N.D., e-mail)
A: Put off pruning your juniper until next March or April, and then give it a good hard pruning. If the plant was healthy and vigorous prior to pruning, it will shoot up all kinds of growth next spring, which you can easily control with touch-up pruning.
The reason for not doing it now is because we are too far along in the season for proper and complete healing to take place prior to winter setting in. This could lead to winter die-back of some of those branches.
Q: Can you tell me the best way to put a clematis to bed? Should I cut them back now? I also have a large ash tree that provides good shade, but the interior branches are dead and leafless. The outer branches look fine, and I cut back the deadwood. Can you tell me what we should do with it? (Moorhead, Minn., e-mail)
A: The Jackman group of clematis, which blooms vigorously on new growth each season, should be pruned back each spring to within 6 inches of last year's wood. It may or may not send up some new shoots from the crown. If these should appear, cut back all old wood to ground level. As the season wears on, pinch back the new growth with your fingernails to encourage branching and a fuller vine.
Some internal branch die-back is normal on all deciduous woody trees. If it continues or becomes extensive, and all the leaves or branches show some necrotic or cankered areas, then some corrective action should be taken. If the tree is really important for your property, I would have a professional arborist come out and give you a diagnosis, along with providing some corrective action to take.
Q: Can you tell me how to winter my strawberry pot? What temperature should I allow it to get down to, and should I clip off the plants before putting it away? (e-mail)
A: I would suggest keeping the pot outdoors if possible. I am afraid of temperature shifts that could tease the plants out of dormancy too early. Here is my suggestion: dig a hole, plunge the pot into it and mulch heavily after the ground initially freezes in October. If this is not possible, get some bales of straw and stack them around the pot. Take another two bales and break them up and scatter them over the pot as well, and cover with a tarp to keep in place after the initial freeze-up.
While you don't want them going into winter dry, you don't want them to be too wet either, or your pot may be damaged. Remember that when water freezes it expands 9 percent, or increases its volume by 11 percent, so the trick is to get the soil frosted, but not frozen hard.
Quite frankly, I have never done this, so this is not advice from experience, just simple logic. If any of our readers have a better suggestion, I'll pass it on to you!
Q: Can you identify this weed for me? It is growing in my neighbors garden, and we want to know how to get rid of it. (LaMoure, N.D.)
A: As close as I can determine, this member of the composite family is known as white snakeroot Eupatorium rugosum. Kill it off with Roundup. I know of nothing that will selectively remove it.
Q: What causes the whitish spots on my lilac bushes and my phlox? (Fargo, N.D., e-mail)
A: The white cast, or spots, on your lilacs and phlox are from a topical fungus known as powdery mildew. This is generally not a serious enough problem to be concerned with. These two species are especially prone to this fungus, which shows up in late summer or early fall, when the humidity is especially high, along with the temperatures.
Simply clean up the leaves, and if you wish, spray the foliage next season with a fungicide to inhibit the development of the mildew.
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Source: Ron Smith (701) 231-8161 ronsmith@ndsuext.nodak.edu
Editor: Dean Hulse (701) 231-6136