NEWS for North Dakotans
Agriculture Communication, North Dakota State University
7 Morrill Hall, Fargo, ND 58105-5665
July 13, 2000
Ron Smith, Extension Horticulturist
North Dakota State University
Q: Would it be safe to spray Roundup on the ash seedlings that are coming up in the rock
around our house? Also, I have a 1.5 gallon sprayer that I would like to use to do it.
Please let me know how to do that. (Gettysburg, S.D.)
A: Ash seedlings should be fairly easy to wipe out. I’d suggest 2 ounces per gallon. If you should accidently get any on the desirable ornamentals, you’ll only get a small foliage burn and not kill the plant.
Q: I have a beautiful gloxinia plant with several large blossoms and many buds forming, but the buds turn brown and die. What am I doing wrong? Am I overwatering? (Glen Ullin, N.D.)
A: It sounds like overwatering is the cause.
Q: I would like to know why our apricot tree drops the apricots and our plum trees drop the plums? We are also noticing that our apple tree does the same. (Bismarck, N.D.)
A: So-called June fruit drop is a normal phenomena. The tree is simply shedding the excess, smaller fruit so that more energy can be put into developing the remaining fruit to maturity. Nothing to worry about or do.
Q: I live across the street from a fertilizer plant and the carpeting on my front porch is covered with green moss. Someone told me it is caused by the fertilizer. If I install new carpeting will it happen again? (Kent, Minn.)
A: Most likely the moss is also encouraged by the weather conditions. If you can, and the moss isn’t too thick, scrape it off and wash down with a chlorine-bleach solution. The fertilizer dust helps in the development of the moss, but the continually moist conditions are the major cause. Getting new carpeting will temporarily solve the problem until the conditions build again for moss to develop.
Q: Could you tell me what is the best thing to do for a Colorado blue spruce tree that has a fair size spot damaged on the trunk? A piece of bark has been scratched off. Should this be painted, wrapped, or what? (e-mail)
A: Take a sharp pocket knife and cut back to attached bark in as even a manner as possible, attempting to create a symmetrical wound. Apply no wound dressing, just keep the tree healthy with regular watering and occasional fertilizing.
Q: Is it OK to use gypsum to reduce salt and pH? I am having trouble getting trees to grow and have found a site on the Internet that recommended this. What rate or how much should I use? (Wahpeton, N.D., e-mail)
A: That is poor information--or at least incomplete information. Gypsum, which is essentially calcium sulfate, is close to neutral in pH value. Second, in order for it to be effective, it has to be placed on a soil that is high in sodium (Na) to have the calcium ion replace it. Third, adding gypsum or anything else will do little to no good if the salts cannot be leached from the root zone or soil profile. Most soils in the Red River Valley are from a calcium carbonate base, so there is plenty of calcium already present, and unfortunately, most of the soils are poorly drained.
If, by chance, your soils are well drained (which I doubt), then adding gypsum might help, if I knew what the amount of sodium per acre was. For every 23 pounds of sodium present in the soil, 20 pounds of calcium is required to replace it. For example then, if a soil test showed 402 ppm (parts per million) sodium, or 804 pounds per acre, roughly 700 pounds of calcium per acre would be required to make the replacement (804 pounds of sodium divided by 23 times 20 = 699). Since gypsum is about 29 percent calcium, it would take 55.3 pounds of gypsum per 1000 square feet to make the replacement. This should be worked into the upper 6 to 9 inches of soil prior to planting, followed by 12 inches of irrigation water applied over a two week period to leach out the unwanted sodium.
I know this is more information than you wanted, but I was trying to show that answers to such problems are not simple, but complex. I suffered through many hours of soil physics to learn this stuff years ago--and back then I was really wishing it was simple!
Q: What can be used to control sowthistle and wild morning glory in my strawberry and raspberry beds? (e-mail)
A: Two tough ones! You could try to spray Roundup carefully on them, trying not to get the spray on the strawberry foliage. Since it is not soil active, it would not hurt the adjacent strawberry plants. There is nothing else I can come up with that you could use in a broadcast manner. Sorry!
Q: Why would rhubarb plants set seedstalks first thing in the spring? (Towner, N.D., e-mail)
A: That simply proves they are sexually mature or established in their site. They should be cut off to preserve food for the stalks and new leaves.
Q: Can I spray my trees with a fungicide to control the cedar apple rust? If so, what fungicide do you recommend? (Mott, N.D., e-mail)
A: It would be far easier for you to pick off the globular galls on the cedars right now than to go to the expense and environmental havoc of spraying a fungicide. Simply removing those gelatinous galls would break the cycle, and prevent the apples from becoming infected.
Q: Can you give me some ideas on why two 20-year-old pear trees located about 100 feet apart in full sunlight don't bear. They seem to be in excellent health and to have escaped frost damage on blossoms most years. Occasionally, each has a few tiny pears. (Jamestown, N.D., e-mail)
A: Same reasons apple trees won't bear: not stressed enough, too much nitrogen, wet/cold/windy (any or all of the above) at the time of pollination. Another reason is lack of pollinating insect activity.
Q: I need a fast growing tree for a screen, and have been considering green ash or cottonwood. I read in a gardening supplement in my local paper about the Austree which can grow 8 to 15 feet per year. Usually when something sounds too good to be true it is. What is your opinion of the Austree? (e-mail)
A: My opinion is zero. You are right, it is too good to be true. This is a cross between a willow and poplar. NDSU has evaluated them at various sites around the state, with the results being that they do indeed grow quickly each year, but then die back every winter to the crown. You are better off keeping your thoughts going in the original direction.
Q: My friends and I have been discussing our peonies and we want to know why peonies won't bloom if they don't have ants on them. What do the ants do to make them open? (Hettinger, N.D., e-mail)
A: Good question! And at the risk of making a sexist remark, the ants causing the peony flowers to open is an old wives’ (gardeners’ etc.) tale! The ants are attracted to the peony flower buds because they secret a sweet sticky substance at that point just prior to opening. I can't tell you how disappointed I was as a young horticulturist to learn that this nice bit of folklore had no truth to it! To get ants off the buds or flowers before bringing them inside, shake them or dip them in warm sudsy water and rinse.
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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