NEWS for North Dakotans
Agriculture Communication, North Dakota
State University
7 Morrill Hall, Fargo, ND 58105-5665
September 3, 1998
Hortiscope
Ron Smith, Extension Horticulturist
North Dakota State University
Q: Enclosed are some needles from my spruce tree that are turning brown. I have sprayed for mites, but I'm not sure if I used the right spray. I was given some Kelthane, but I don't know how to use it. Also, is the other enclosed sample a weed or a flower, and will Poast kill Kentucky bluegrass? Is it OK to transplant in the fall, and when is the best time to sow poppy seeds? (Winner, S.D.)
A: Some mite damage was noted on the sample needles you sent. The best, most effective material to use is a hard spray of plain water once or twice a week. Folks in the business to sell miticides don't like hearing that, but it is true!
A weed—member of the buckwheat family—get rid of it before it goes to seed. Poast is a grass herbicide; therefore it will kill Kentucky bluegrass. The oil concentrate can be obtained from your local elevator or pesticide supplier.
Transplanting of trees and shrubs can take place up until the soil freezes. The earlier the better. Perennial flowers are transplanted after they have been blackened by frost. Best to do it early too.
You can dormant sow poppy seeds in October, around the 10th through the 15th, or early in the spring as soon as soil can be worked.
Q: I am sending a sample of an 3-year-old autumn leaf maple. It seems like the leaves are drying and the tree doesn't have much new growth. I have been told it needs iron, so I have been feeding it with iron and fertilizer. Can you help me? (Napoleon, N.D.)
A: The symptoms on the leaf samples indicate a strong possibility of iron chlorosis. It could also be the result of planting too deeply or poor drainage.
If it is possible to move it, do so. The tree certainly isn't going to survive where it currently is. When you move it to a new site, set the tree so that the "knob" or graft union between the scion and root stock are level with the surrounding soil. Be sure a circular area of about 2 feet is clean or clear of turfgrass around the trunk. Water in with a solution of Miracle-Gro or Miracid when planting.
If the tree dies, you will at least have the satisfaction of giving it your best shot at trying to save it!
Q: For the last two years, my crabapples have had this scab on them. What can we do to prevent this? (Wilton, N.D.)
A: The scabby fruit is still edible, just not as attractive. Go ahead and make apple sauce with it and enjoy!
Next year at petal drop, spray with a fungicide like Captan or Chlorothalonil. Repeat in 10 to 14 days. If only one or two branches are covered with tent caterpillars, prune them out and burn.
Monitor the tree next year and if you should see an infestation getting started, spray with the bacterial insecticide Bt (Bacillus thuringiensis).
Q: Could you identify these plants for me? The large leaf came up next to our deck and the small one I got at a fund-raiser. I thought the small one was supposed to bloom, but it hasn't yet. I also would like to know when to transplant the small one. (Ponsford, Minn.)
A: The "big leaf one" is a boxelder maple—Acer negundo—while the small one is alpine current. You should be able to transplant this anytime after the leaves drop and before the soil freezes.
You need to make a decision on the maple. If it is too close to the deck, damage could occur as the tree matures. If it is something you want to keep, move it this fall when it is dormant.
Q: I have enclosed a small branch from my red maple tree that was a gift 10 years ago. For the last few years the leaves have started to turn yellow and drop off. I have tried fertilizer spikes and iron granules, but I don't think it is helping. Also, is the white cocoon a limb worm? (Breckenridge, Minn.)
A: The tree was a thoughtful gift, but an inappropriate selection. This species is not well adapted to our area. The white cocoon on the limb is a cottony cushion scale insect. They usually get established on trees and shrubs that are under stress. Which yours obviously is.
I have enclosed an extension publication, "A Guide to Deciduous Tree Knowledge" (F-436), which should help you make better future selections.
Q: Could you identify this leaf for me. It is growing quite fast and is really tall already. (Warner, S.D.)
A: Your tree is a little leaf linden. A beautiful tree throughout its life. Take good care of it!
Q: How much and when do silver lace vines require pruning? You have recommended Poast and Confront for various weeds, but I cannot purchase these brands. Can you tell me what the chemical bases are for these two? (Mobridge, S.D.)
A: The silverlace vine (Polyganum aubertii) can be mowed whenever the spirit or need to motivates you! You can do it with clippers, electric shears or just a mower! Don't worry about killing it!
There are plenty of other products on the market that can control weeds: Trimec for broadleafed weeds and Ornamec for grasses. There is also Weed & Grass Preventer, Surflan, Grass Out etc. The ones I mention are merely examples and some I have worked with.
The active ingredients in Confront are triclophr and clopyralid. In Poast, the active ingredient is ethoxyimino-butyl-3 hydroxy-2-cyclohexen. I must hasten to caution that no matter where you find these active ingredients, off-label use is considered a violation of the law.
Q: Can you tell me how I can control the spread of hollyhocks all over in my yard? (Maddock, N.D.)
A: Any broadleaf herbicide that you would use to control dandelions or plantain would also coincidently control the hollyhock. If they are in an isolated area, you may use Roundup for their control. Remember, it is a nonselective herbicide, so be careful where you direct the spray.
Q: I have had my poinsettia plant outside all summer, and it has grown a lot and looks healthy. I am wondering when I should start putting it in a dark place and for how long? Also, should it be fertilized? (Mayville, N.D.)
A: Enclosed is a publication on poinsettia culture, "Poinsettia Care in the Home," (H-906). Basically, the sooner you begin giving it "long nights"—that is more than 12 hours of darkness—the sooner it will set the colorful bracts. Generally, providing these conditions by Oct. 1 will yield a colorful plant in December.
Q: We have a cateoneaster hedge, and we are wondering how to properly care for it. (Carrington, N.D.)
A: With the hedge, you can cut it back to the ground next spring and it will shoot up new growth again.
Q: We have two apricot trees that keep dropping the fruit before it gets ripe. What can we do to stop this? (Wahpeton, N.D.)
A: Usually complete fruit drop indicates grub infestation, poor fertilization, and/or wide moisture fluctuations. I suggest trying a spray of Sevin or Malathion next spring as the flower petals begin to fall.
Q: Can you give me some information on dry rot of tomatoes? (Carrington, N.D.)
A: I assume by dry rot you mean blossom end rot. I've addressed the subject several times throughout the years and will be happy to do it again. Blossom end rot is not a disease per se (not caused by a pathogen), but a condition where insufficient calcium is available for complete cell formation at the blossom end of the fruit. This causes tissue breakdown, which results in the "rot" that is seen.
This is caused in some cases by wide fluctuations of water availability, cultivation or other root injury, and it is simply a characteristic of some tomato cultivars, with the first fruit to ripen being most vulnerable.
No sprays! Just maintain an even moisture regime, mulch, and select cultivars that are not prone to develop this malady.
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Source: Ron Smith (701) 231-8161
Editor: Dean Hulse (701) 231-6136