NEWS for North Dakotans
Agriculture Communication, North Dakota State University
7 Morrill Hall, Fargo, ND 58105-5665
May 18, 2000
Ron Smith, Extension Horticulturist
North Dakota State University
Q: I moved a pink rose shrub (the variety was never known to me) and apparently a little root was left behind for a new rose grew up in its place. It has not flowered yet but I am wondering if there is any chance of it being a clone of its parent. I thought it would not be, as many roses are grown on different root stock. But perhaps rose shrubs are a unique case. The reason I ask is the parent plant is failing and I thought if it was a clone I'd use it instead. It hasn't flowered yet so I cannot tell you much more. Perhaps I'll just have to wait and see what flowers it produces. (Fargo, N.D., e-mail)
A: It may or may not be a clone of the parent. Check the parent bush and see if there is a knot where the bud graft was performed (at the base of the plant). If there in none, then the sucker growth you see coming from the root is indeed a clone. If not, then it is likely a hardy rose stock not known for any great flowering ability, just hardiness.
Q: I've read that there are new oak hybrids: Dakota Sunrise Bur Oak, and Mongolian Oak. Where can I buy such trees? I don't have the slightest idea who would sell them? Also, is there a book about the bur oak? I know these would be unlikely, but I have many in my area, and they are my favorite tree. (Hawley, Minn., e-mail)
A: When new hybrids like this are first released, they are often difficult to locate, but keep asking at locally owned garden centers, as they are most likely to be getting such stock shipped in. Perhaps someone can special order it for you.
I know of no book dedicated specifically to the bur oak.
Q: Is it possible to propagate clematis successfully by root division? If so, what is the best way of doing so? (Biggar, Saskatchewan, Canada, e-mail)
A: Propagation of clematis can take place a number of ways: seed, cuttings, grafting, root division or layering. Of all those choices, the easiest way to propagate them is via cuttings taken from young wood in the spring, but semi-mature wood taken in late spring also works and is more commonly used commercially.
Perhaps the easiest way to propagate this species is by layering. Simply bend one of the stems over and pin it into the soil, allowing the tip to remain upright and in the daylight. It should root in about four to six weeks.
Q: I would appreciate any advice you can give me regarding two apparent problems with my purple-flowered gloxinia. I was given the plant about a year ago, and I transplanted it about four months ago. Some of the leaves have several brown spots on the bottom but otherwise look perfectly healthy. What are the spots? The plant has been flowering like crazy, but unlike the first set of flowers, there are several white patches or spots on the flowers now, and it doesn't look healthy at all. Have you ever heard of this problem before or do you know what it could be? (Toronto, Ontario, Canada, e-mail)
A: What I'm providing in my answer relates to the florist gloxinia--Sinningia speciosa. Gloxinias are not very forgiving of any human misgivings. They need to be kept moist--moist soil, not the foliage--with tepid water. They require high humidity, which is accomplished by placing the plant on a water-filled pebble tray. They also need bright, but indirect light--no direct sunlight. Allowing the sun's rays to reach the plant would be one of many causes of spotting on the foliage and flowers.
As a sweeping generalization, it is usually the dry air of winter heating units that causes the most trouble. That, or a cold draft of air could cause the same problem.
Finally, your plant could be trying to go dormant. Normally, gloxinias are purchased as tubers in the spring and brought into flower in summer. I suggest that you may want to allow your plant to go dormant, which may last four to six weeks, or just a few days. You'll know when that period is over when new shoots become visible. Then start the cycle over again.
Q: What granular herbicide would you recommend for weed control around trees in yards? The trees have a rock bedding around them with railroad ties at the borders to keep grass out, but weeds are still a big problem. There are both hard wood and conifers in the yard. Price, of course, is a consideration. (Amidon, N.D., e-mail)
A: Nothing works better and is safer for trees than Roundup. Just remember that it will kill anything green--green bark, green leaves--but Roundup is not soil active, so it will not be taken up by the roots. It is also comparatively economical.
Q: I have three snowball bushes which are about 12 years old. The last three years the leaves have begun to curl and turn black and there are tiny bugs in the leaves. Is there any spray I can use now before the leaves come to kill the bugs? Any help you can suggest will be greatly appreciated. (Berthold, N.D.)
A: Spray the plants with Orthene. This is a systemic insecticide that is effective at killing piercing, sucking insects.
If by chance, the leaves have not yet opened, you can spray the plant with dormant oil. This will kill any over-wintering eggs and will be safer for you to handle. If they have leafed out, don't use the oil as it would very likely be phytotoxic.
Q: There is a canker or a gall on one of our "tower" poplar trees. It is about 4 feet up on the main trunk of the tree, looks like a big wart. It goes about half way around the tree and is dark brown, blackish and very hard.
Should we try to cut it out or should we spray it with something? Would appreciate whatever information you have. (Pettibone, N.D.)
A: What I think you are describing is known as a "conk." These conks or fruiting bodies of Basidiomycetes, are indicators of advanced decay, resulting in your tree becoming increasingly structurally weakened.
This requires a judgment call on your part and you are better to err on the side of plant removal than keeping it around too long where it could cause damage to property or person. Cutting the gall or conk out will not solve the problem, as the area around the growth is loaded with spores. From your description, I would suggest removal of the tree and replanting with something else that is healthy.
Q: What product should I use to control grass in my asparagus this summer? (Pelican Rapids, Minn., e-mail)
A: There are several that can be applied. Just follow label directions.
- Treflan--preplant only; not good on emerged weeds.
- Poast 1.5E--very effective on quackgrass at high dose.
- Fusilade DX 2E--can use only on non-bearing crop.
- Roundup Ultra--apply either seven days before first spears emerge or after the last spears have been harvested.
Q: I am having quite a bit of trouble with blight in my tomatoes and potatoes. Will the addition of copper to the soil help with the problem? I know of people in Williston that do apply copper and it seems to help. What do you think? (Amidon, N.D., e-mail)
A: Perception is everything, and if the copper seems to work, then so be it. But don't over do it, or plant toxicity will be the result. Copper IS a micro-nutrient, meaning that very little is needed for the effect desired--20 parts per million max. I would rather you apply the needed copper (and other micro-nutrients) through the use of a product like Miracid or something similar. That will reduce greatly the chance for toxicity.
Q: Perhaps you can help me then. I have a plum tree problem where many of the leaves, particularly the new ones, are curled and wrinkled up (though still green). There are also similar leaves that are brown and dry, apparently the same problem in its latter stages. Any Ideas? (Sunland, Calif., e-mail)
A: From your description of the leaf damage, it sounds like a fungal disease known as plum pockets (Tapheina pruni). You didn't say anything about the fruit being swollen, which is a more obvious symptom, so I suspect that my diagnosis could be incorrect.
You may want to try some control applications of approved fungicides like Bordeaux mixture or Ferbam. They both are broad-spectrum fungicides that should take care of the problem.
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 firstname.lastname@example.org.
Source: Ron Smith (701) 231-8161
Editor: Dean Hulse (701) 231-6136