NEWS for North Dakotans
Agriculture Communication, North Dakota State University
7 Morrill Hall, Fargo, ND 58105-5665
December 2, 1999
Ron Smith, Extension Horticulturist
North Dakota State University
Q: What spray can I use to control leafminers? What causes the bottom leaves of my delphinium to die? There is something wrong with the leaves of two plants I have. I think one is an oak of some sort and the other is a Holland ivy. (Carrington, N.D.)
A: There are several sprays that can be used for leafminer controls. Sevin, Malathion or Orthene. Spray at first sign of damage, and repeat as necessary. Be sure to check for plant sensitivity of any particular insecticide by reading the label.
I have no idea what causes the lower leaves of your delphinium to die. It could be any number of factors such as nutrient deficiency, a fungal disease or environmental stress. It could also just be normal senescence.
The leaves are showing salt damage symptoms. The containers are either not freely drained, kept too wet or the natural water salts--dissolved solids--are too high.
Q: We are thinking of replacing some old trees with a poplar and a Russian olive. Do we need to worry about the roots that are left from the old trees?
Also I have been planting wave petunias every year since they came out, but this year they only had about half as many blossoms as other years, and the leaves were real slender. Other people we talked to had the same problem. We have saved some seed, but we are wondering if it could have been caused by the weather? (Litchville, N.D.)
A: You are OK! Any remaining root material will simply rot and eventually provide nutrients to the newly growing trees.
The petunia was a fluke. And, I doubt you will get anything at all like the wave petunia from the seed you saved.
Q: I have had a large peace lily for two years which I repotted six months ago. I didn't disturb the roots very much, but since then it has sent up so many new shoots so thick they can't get up through the older leaves. This plant means so much to me I don't want to lose it. What should I do with it? (Howard, S.D.)
A: The peace lily needs dividing and repotting. Use a pure humus, or at least a very high humus potting medium for the task. It has been my experience these plants are tough to kill. Direct sunlight and cold drafts are damaging; otherwise, just keep it watered and fertilized.
Q: We have a book on all different insects and it talks about if you have aphids that you shouldn't plant cucumbers, pumpkins or squash for one year. We did that but it did not help. This summer we got very few cucumbers. They came up really good and as soon as they started vining out the problem started. The leaves start to curl, get dry around the edges and then the vine starts drying up. We have sprayed and powdered, but nothing seems to help. Do you have any idea what it could be and what can we do about it? Is there something we could put in the garden to get rid of the problem? (Stanton, N.D.)
A: The first thing I would suggest is a soil test which will cost less than $20. Get the pH, soluble salt, organic matter, and the nitrogen, phosphorous and potassium (N, P and K) tested. Send about a pint of soil to NDSU Soil Testing Lab, Waldron Hall, Fargo, ND 58105. Something must be wrong with the soil, I suspect, for the plants to react that way consistently.
Q: I have been trying to get rid of a weed, but with no luck so far. What can I do? (Pelican Rapids, Minn.)
A: Your weed is creeping Charlie, a tough, deep-rooted perennial that doesn't surrender easily! I suggest an aggressive treatment starting with Trimec, as soon as growth begins next spring. Set your mind for at least a couple of applications to get it under control.
Q: I have an answer for the person who wrote about the vine with heart-shaped leaves and turban-shaped purple flowers. It must be Solanum dulcamara, sometimes known as "deadly nightshade." It's a very invasive weed, but great for hiding ugly fences or sheds. Also, potato beetles love it! (Fargo, N.D.)
A: You're right! I've received several responses to that question all saying the same thing. For some reason, deadly nightshade did not occur to me. I just was not thinking herbaceous!
Q: Help! I'm tired of putting plastic bags and empty pop bottles on my apple trees. The deer ate the bark and part of the branches off last winter. The trees are going on 9 years old and were producing well until last winter. What solutions can you give me for preventing the deer from eating my trees? (Portland, N.D.)
A: Deer control is very difficult! First, I believe they are more intelligent than we humans have given them credit for in the past. Second, anything that works initially has not worked very well in the long run. Finally, it all depends on how hungry they are. If they are truly starving, nothing short of a bullet will stop them, which, of course, is not an option unless you're a licensed hunter and the season is on.
Human hair, deodorant soap, and urine from predatory animals will work, with the last being most effective. Visit your local garden center and request they purchase one or more of the following: wolf, coyote and mountain lion urine. One source for these products is Hummert Seed Co. in Missouri.
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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 .
Source: Ron Smith (701) 231-8161
ronsmith@ndsuext.nodak.edu
Editor: Dean Hulse (701) 231-6136