NEWS for North Dakotans
Agriculture Communication, North Dakota State University
7 Morrill Hall, Fargo, ND 58105-5665
August 5, 1999
Ron Smith, Extension Horticulturist
North Dakota State University
Q: I received a miniature rose bush for Mother's Day, and I am wondering if I can plant it in the ground. Should it be in full sun and when is the best time to transplant it? I also would like to know the names of some self-seeding annuals. (LaMoure, N.D.)
A: Roses like full sun early in the day, as it helps to keep black spot and other leaf diseases under control. Plant it after it goes dormant this fall. Be sure to give it plenty of winter protection.
Now, for some self-seeders--my favorite kind of flowers:
- Nigella, or love in a mist. Nice feathery foliage, bluish, lacy flowers. Seed pod dries beautifully.
- Nicotinia sylvestris, or giant flowering tobacco. Nice fragrance. Be sure to plant in back of the garden.
- Verbena bonariensis--small purple flowers will show up everywhere.
- Cleome, or spider flower. A good tough one to withstand our prairie winds. A nice range of colors and tall--3.5 to 4 feet--but not as tall as the flowering tobacco.
- Others include poppies, columbine, borage and forget-me-nots.
Q: Can you tell me why the leaves on my crab apple trees have a wilted and blotchy appearance? I began using a fungicide for leaf scab at seven-to-10-day intervals, but I think I may have been too late. When is a good time to spray them and should I use a fertilizer this fall? I heard that fertilizing apple trees can promote rapid growth and fireblight. Is that true? (Fargo, N.D.)
A: Fungicidal sprays should be applied as the leaves open. You can use chlorothalonil, which is probably the best selection. I find that using lime-sulfur as a dormant spray prior to leaf-out can also aid. You are right--fertilizer can cause excess growth and can lead to fireblight.
Q: I have hollyhocks that have been growing on the east side of my house for 40 years or more. The past three years the leaves have become spotted and eventually the leaves turn brown and fall off. Please help me get them back to growing and looking nice again! (Sheldon, N.D.)
A: Wow! Forty years in the same location--that's amazing for herbaceous plants.
You've got a couple of fungi working against you: a leaf spot and rust. You can try controlling these problems in several ways: one, good litter clean-up this fall; two, pre-emptive spraying with bordeaux mixture to control the leaf spot; and three, pre-emptive spraying to control the rust--this time using Maneb or Zinebor, or if you can find it, powdered sulfur.
Q: Can you tell me why my clematis leaves are turning yellow? Also, how do I get my Christmas cactus to bloom? (Wimbledon, N.D.)
A: Classical symptoms of manganese (Mn) deficiency! Could be brought on by poor drainage or low organic matter content in the soil. Another possibility could be excess iron being available from a chelated form being applied.
When the interveinal chlorosis shows up on older foliage like this, and the new growth appears normal, it is manganese deficiency. Iron deficiency shows the same symptoms, but on the new growth only.
What to do? There are several manganese formulations available. I would suggest looking for a Mn EDTA chelate or an organic complex. This is a trace or micro-element, so not much is needed. If you have not mulched the clematis with peat moss or compost, I'd suggest doing so.
Q: I planted two bleeding hearts and they are steadily disappearing on me. What is wrong with them? The leaves on my geranium look tight and curled, what is the problem? Some of my tulips came up this spring, got a large white leaf, and did not develop a flower. Why? Should a perennial flower garden have something done to the soil to give plants an extra boost? Also, what is wrong with my rose bush--the leaves are slightly brown? (Munich, N.D.)
A: It is the natural character of the bleeding heart to die down after flowering in the spring-- nothing to worry about. They will reappear next spring.
Your geranium has a couple of maladies. One you already named, crinkle virus, and another--a heavy infection of sooty fungus.
Do you have a bunny population? They love my tulips! It could also be that some did not have a sufficient cold treatment or were too immature to produce a flower this year. I suggest patience!
As for your perennial garden, work in quality compost or sphagnum peat moss in the upper 6 to 9 inches before planting. Mulch with the same.
The roses have something wrong in the root system--too much fertilizer, water or whatever.
Q: Can you tell me what is wrong with my North Blue blueberry? The leaves are curled under and don't look very happy. (Sioux Falls, S.D.)
A: The blueberry problem could be related to the pH of the soil. The reading should be around 5.5.
Q: All the oaks in Lisbon seem to have the same problem that my 5-year-old oak is having. Please let me know how to fix it. (Lisbon, N.D., e-mail)
A: You have nothing to worry about concerning the galls you see on the bur oak foliage. These galls are caused by a nonstinging miniature wasp laying eggs in the unfolding foliage in the early spring. The actual galls are believed to be caused by plant growth regulating chemicals that are produced by the insect. These and other galls are so commonly associated with oaks that people regard them as typical structures of the plant--that is, considered "normal."
Yours is called the "jumping oak gall," caused by Neuroterus saltatorius. After the larvae hatch they move so violently they actually cause the gall to move or jump. At the stage you are now noticing them, the insect inside the gall has already departed. So what you are seeing is the "former home" of the young.
No action is suggested or warranted. Just your normal care of the tree is all that is needed. Keep in mind that these characters evolved together eons before mankind ever realized their existence!
Q: I have a weed in my yard and was wondering if I can control it with 2,4-D or Weed-B-Gon. (Oberon, N.D.)
A: Your yard is sprouting oxalis. Yes, you can control it with 2,4-D or Weed-B-Gon. Expect to do repeat applications because this plant is a prolific seed producer. Work on getting your lawn in shape so this doesn't have a chance. Mow high and fertilize two times per year.
Q: Can you tell me what is wrong with my chokecherry tree? (Battle Lake, Minn.)
A: Your tree is being bedeviled by a blister gall mite and by a fungal disease. Anything you do now will be a waste of time and money.
In the fall, clean up all fallen leaves and fruit. Then, next spring apply lime-sulfur and dormant oil on the tree just before the buds open. When the leaves are about one-third unfolded, apply Orthene. This will help to control the mites somewhat. Then as the blooms drop, apply bordeaux mixture to control the fungus. Repeat again in 10 days. This procedure should help your tree significantly.
Q: We have tried every kind of slug and snail killer, but we cannot seem to get rid of them. Could they have been brought in with old manure? If we don't plant anything for a year or two, would the slugs go away? (Eureka, S.D.)
A: Yes, they could very easily have been brought in with old manure, but everybody has slugs this year--even yours truly. When we find huddles or clusters of slugs, I sprinkle salt on them and that takes care of the cluster. Controlling your watering somewhat will also work to reduce the population. Keep trying. Things will improve!
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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