September 11, 2003

Hortiscope

Ronald C. Smith, Horticulturist
NDSU Extension Service

Q: During this dry spell, some weeds started growing in my lawn that look scary. Last year you identified one as knob weed. Another weed I have looks somewhat similar but has a broader leaf. Could it be chickweed? Both of these plants seem to endure heat and dry weather very well. How do I treat it and can I use the winterize fertilizer and weed control product? When can I use it? (Portland, N.D.)

A: The winterizer fertilizer can be applied separately from pre emergent weed control, which you want to apply early next spring, before the forsythia comes into bloom. Both will be more effective and you will get more bang for your buck.

Q: We've lived in our house for about eight years. With the house came a garden with a well established Japanese maple. This year, some branches are dead looking and some leaves on the rest of the tree are beginning to turn brown. The trunk and bark has started to tear. It seems to be dry underneath the dead-looking branches. I'm assuming this little guy won’t make it. Do you know what might have killed it or can it be saved? (E-mail reference)

A: It is unfortunate to lose such a beautiful tree. Not knowing where you live, it is hard for me to give you accurate recommendations as to what may have caused the decline. Japanese maple declines more from poor cultural practices than from insects and diseases. This is a species, depending on the cultivar, that needs a lot of attention early on. It needs high organic matter soil, good drainage, ample moisture and a lot of care to bridge it through times of extended drought or excessive heat. That doesn't mean that your tree couldn't be succumbing to a root rot fungus or being attacked by borers. I would encourage you to contact a certified International Society of Arboriculture arborist to inspect your tree to find out what the problem is. The arborist will be able to tell you what corrective action to take to reverse it or avoid it in the future.

Q: I am in the process of developing several 4- to 5-acre shrub plantings for wildlife. The shrubs I am using come from a list by the N.D. Game and Fish Department. The list includes chokecherry, silver buffaloberry, silverberry, American plum, Arnold's hawthorn, snowberry, red osier dogwood, skunkbush suma, woods rose and Juneberry. Is it possible or practical to grow any of these plants from seed? I would like to try it on a limited basis. It would be fun to have some plants propagated from seed and would give me some personal satisfaction. I've planted about 5,000 so far and am planning on another 15,000 to 20,000 over the next 10 years. (Robinson, N.D.)

A: Yes, it is possible to grow each one from seed. I suggest getting a hold of a book on plant propagation or Dirr's book, Manual of Woody Plants. In it he mentions the best methods for propagating each of the species, either by seed, cuttings, division, or other methods.

Q: The leaves on my double impatience houseplant are curling. It gets plenty of water and does not have bugs. (Linton, N.D.)

A: Check the underside of the leaves for spider mite activity. If that isn't the problem, then it could be that you are over-watering the plant.

Q: I looked at a creeping juniper in a yard that was planted two years ago. The center of it has a lot of dry needles and appears to be dying out. Would an application of Miracid help? There do not seem to be any factors in the yard affecting the area. The other plants are doing well so I don?t think it is a lack of water. The junipers are on the east and northeast side of the house so they do not get the intense afternoon heat. (Forman, N.D.)

A: Creeping junipers have a nasty habit of doing that as they age, just because they age! Applying fertilizer will not force new growth from the center but a pruning may. This is one of these tightrope operations. The plant isn't going to look any better being left alone, so you might as well prune it to see if any new growth emerges. If it doesn't, then the plant is dead and can be replaced.

Q: I have a large, old cottonwood tree in my backyard that is probably 50 years old. It sends up shoots on the exposed rootballs all over my yard. Is there anyway to discourage these shoots while not harming the tree? (E-mail reference)

A: Use a material called Sucker Stopper RTU. It is available at some retail outlets. You may want to contact the company directly to find the nearest location. They can be reached at Monterey Lawn and Garden Products, Inc., Fresno, Calif., (559) 499 2100. Or contact them on the Web at: www.montereylawngarden.com  . It is fairly pricey stuff so use it with discretion.

Q: Our lawn was recently sprayed with Trimec but the wind carried some of it into our vegetable garden. Is the produce safe to eat or is there a time period we should wait? Should we treat them with something? (E-mail reference)

A: Is there symptomatic evidence the spray impacted the vegetables? If so, then they should not be eaten. If there is no evidence, then follow normal washing and rinsing precautions.

Q: We have a rather large jade plant (Crassula) that has been doing extremely well for more than twenty years. This winter I noticed two or three fairly large areas in the trunks that looked damp. One of them became quite slimy. The others have a very light slime. When we moved it outside this spring, we repotted and saw no evidence of rot. This condition does not seem to bother the plant. The leaves are fine although new growth is slow. There is some minor brown scaling. The slime is clear and has the consistency of warm Vaseline. The spots have neither grown nor diminished in six months. (E-mail reference)

A: My only guess is that you have a limited oystershell or San Jose scale problem in those areas. Some scale will secrete the excess plant fluids they take in which is called honeydew. If that is absolutely not the case, then it could be a limited canker infection that has not had the ability to compartmentalize itself due to the slow growth. If it doesn't seem to be affecting the overall health of the plant, then I suggest simply monitoring the sites where these slimy areas are developing. One last thought: it could be a borer of some kind that has taken up residency. Look carefully and see if there is a small hole about the size of pencil lead in the middle of the slimy area. Other than these suggestions, I am at a loss. I’ve never heard of this problem before.

Q: We have a sand play area that we would like to turn into a garden plot. It has about 4 to 6 inches of sand. I intend to put edging around the plot and have some black dirt hauled in. I'm wondering if I can leave part of the sand as a base? How much black dirt should I put on top? Should I try to mix the sand into the black clay that is underneath the sand? Would I be better off getting rid of all the sand and mixing organic material into the gumbo instead of hauling in dirt? Also, the garden that I am using now is in a low spot with poor drainage. I'm planning on turning that in to a raspberry patch. Would it be a good idea to mix some of the sand into that area before I plant? (Fargo, N.D.)

A: The less stratification of the various soil components, the fewer problems. To get the best garden spot developed, remove all the sand, bring in some sphagnum peat moss, till it completely into the existing clay soil, and bring in some more to raise the area from the surrounding terrain. Raised bed gardening will provide superior drainage, earlier warm up of the soil, and in general, better vegetable crops. Sand mixed with clay is an incompatible combination unless it is at least an 80 to 20 ratio. It would need to be 80 or more parts sand to 20 parts clay. I would prefer to work sphagnum peat into the clay because the results will be more predictable.

Q: I just moved a Carol Mackie Daphne and am wondering if I should cut it back to reduce the stress while it settles in. I root pruned it prior to moving it but many of the smaller roots were lost when I planted it so I’m afraid the bush will die. (E-mail reference)

A: That type of plant is very fussy about the way it is treated. At this time of year, assuming you live somewhere in the northern half of the U.S., I wouldn't remove any more of the top than necessary as it is needed to produce carbohydrates that will help build the root system. If it dies unexpectedly, don't be surprised.

Q: How do I grow an Ohio buckeye tree from a seed? Do I just plant it in the ground or do I have to let it have a cold treatment? (E-mail reference)

A: By planting it in the ground at this time of year, it will get the necessary cold treatment for growth next spring.

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. Note to e-mail correspondents: please identify your location (city and state) for most accurate recommendations.

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Source: Ron Smith, (701) 231-8161, ronsmith@ndsuext.nodak.edu
Editor: Rich Mattern, (701) 231-6136, richard.mattern@ndsu.nodak.edu