July 25, 2002

Hortiscope

Ronald C. Smith, Horticulturist
NDSU Extension Service

Q: We have a little-leaf linden in our back yard that has grown much too tall and too wide for the space. It is with great reluctance that we have to have it removed. Do you happen to know if the wood of the linden is "good" for anything? As I see it, our choices are: have the people who take the tree down haul the wood away, just stack it and dry it for burning (we have neighbors with fireplaces and wood stoves), or try to contact woodcrafter-type people who might be interested in working with it. Do you have any suggestions?

A: You are a very conscientious person! In the long run, it would be easier to simply have it cut down and hauled away. If you have it cut to firewood size, there will be a premium charge for doing so. And woodcrafters may or may not want it, leaving you with a pile to dispose of.

Q: The problem I have is my 8-year-old "snowball" tree (I'm unsure of it's real name but I do know it is from the lilac family) seems dead. This spring it had a few buds on it, then it froze and nothing else happened. It had always been very healthy, and chock full of snowballs. It stands about 8 feet tall. It looks dead and the branches are brittle. My husband wants to chop it down. I say wait till next spring. Can you give me a little advice? I really hate to lose it. ( Enderlin, N.D.)

A: In 99 percent of these cases, I side with the women simply because they are right! But, in this very rare instance, I have to give the nod to your husband's objective. If it was going to "regrow" from the crown, it would have done so by now. That said, if this is going to cause disharmony in a marriage, then I would suggest that it stay for another year (what harm would come from doing so?), then remove it if it doesn't live up to expectations.

Q: I love asparagus so I bought one plant from a greenhouse. I planted it this spring and know it will be two or three years before it produces. I haven't done anything to it except weed control and water it. It is growing but I don't know what its suppose to look like or if it will produce sort of like rhubarb. What care do I need to do? (Jamestown, N.D.)

A: It should be in the "fern" stage right now. Just let it grow, and scatter some 5-10-5 or 10-10-10 fertilizer over the area this fall. You can begin harvesting some of the spears next spring.

Q: I have some mock orange and snowball shrubs that I want to trim and wonder what is the best time to do this. I trimmed them last year after they bloomed and thought they did not bloom as well this year but we are in an extreme drought here and watering can't measure up to mother nature. (E-mail reference, South Dakota)

A: The best time with most flowering shrubs, including mock orange, is to prune them right after flowering. It has been pretty much the same all over, poor flowering on what are usually shrubs that flower heavily. I think our wide swings in winter temperatures is what caused the problem in part, along with the current drought in some parts of the region.

Q: My potatoes are not blooming. Will they still produce any tubers? (Linton, N.D.)

A: They should, but that depends on the cultivar you are growing.

Q: My mom has a hibiscus plant and it has been doing really well, but now some leaves are turning yellow, would you know why? It sits in the south picture window and gets plenty of sun, she waters it every other day. She takes really good care of it. (Beach, N.D.)

A: Only a guess that it may be attempting to enter into an early two to three month rest period. She might try backing off on the watering, allowing the plant to defoliate, and water only enough to keep the soil from drying out. If it is still putting out new growth, have her fertilize with a houseplant material to see if that improves things.

Q: I was wondering the differences between fire blight and sodium damage in apple/pear trees. Are the black "scorched" leaf margins common in both? It has been very hot and very dry here (10 percent humidity and less). (Bowman, N.D.)

A: They are common to both, but the difference is that the salt scorched leaves are usually brittle and begin on the margin, with the branches having no "shepherd's crook" at the end, which fire blight damaged branches have.

Q: Last year I planted 11 "Moonbeam" coreopsis in an east-facing bed along a sidewalk. Two plants came back very healthy and have no problems at this point, five did not come back at all and I had to replant with new. The remaining four plants that did come back this year were very sparse yet appeared healthy and began flowering, but in the last couple of weeks portions have started dying off. This has also began happening to one of the new replants. Could they be too wet? They were watered lightly to moderately every other day, as it has been so dry here, and have not been watered in over a week since we received a couple inches of rain. Last year we also planted a cotoneaster hedge with small plants from the local county conservation district. Many of the plants this year are splitting at the base, just cracking down the middle. Some appear to be staying alive despite this, while others have a large portion of the plant that lies on the ground until it finally dies off. Is it normal for cotoneasters to do this? (Aberdeen, S.D.)

A: This sounds ever so much like a disease problem, which could be exacerbated by overhead watering and the high temperatures we have all been suffering through. My best advice at this point: spray with an all-purpose fungicide. Splitting and dying is not normal for cotoneaster or any other woody plant material. My guess it was kept too long in cold storage before you received it for out-planting. Generally, when the material has begun to sprout in storage or kept too long, the transplants lose vigor and have difficulty establishing unless all is just about perfect.

Q: I would like to replace five evergreens which are in the corner of my yard with new ones. The present evergreens have branches that have turned brown and died, starting at the bottom and going about halfway up the trees, a process that has been continuing for the past several years (we sprayed the trees twice a few years ago). Would it be okay to replace the trees in the same location, or might the same thing happen to the new ones? Also, I have three clump birch trees in my yard, one of which is flourishing beautifully, and the other two have branches that did not leaf out, especially on the top third of the trees. They also have yellowish looking leaves in comparison to the healthy one. Is there anything I can do for those trees? (Mayville, N.D.)

A: Replacing with the same species that has died out is never a good idea. It they were Colorado spruce replace them with Black Hills spruce or Ponderosa pine. The clump birch that are showing symptoms are likely being attacked by borers, which are very difficult to control once they get started. If you can locate a certified arborist in your area, you might want to have the trees treated to prevent their further spread and destruction.

Q: What is the difference between lime, calcium, and bone meal? How should they be used and for what plants? (New Rockford, N.D.)

A: Good question: Lime is either calcium carbonate, calcium sulfate (gypsum), calcium hydroxide (hydrated lime), or calcium-magnesium carbonate (dolomite). All have slightly different purposes for horticultural use, and as you can figure out, all come from the earth. Bone meal is an animal by-product, and comes either raw or steamed. The difference is the steamed bone meal that is commonly used in horticulture has most of the gelatinous material removed through the steaming process while the raw bone meal does not. Bone meal is a rich source of calcium as are the many forms of "lime." To "lime" a soil means to add crushed limestone (passing through #60 mesh screen) to adjust the pH from an acidic to a more alkaline or less acid state. This is a chemical reaction that takes time to react, often over several years of application. Dolomite is a good one to apply to provide the essential elements of calcium and magnesium; gypsum supplies the elements of calcium and sulfur, and cancel each other out for the most part, neither raising or lowering the pH of the soil.

Q: We have a variety of hosta plants on the south and east side of our home. The leaves of the plants on the south side are starting to turn brown on the edges. It seems to be limited to the variegated type of hosta, not the solid green hosta. Would heat be the cause or has a disease set in? The east side plants are doing so well and they are of the same variety as the plants on the south side. (N.D.)

A: Yes, variegation will subject the plants to a greater tendency for foliar burn. Mine are doing the same thing. Nothing to worry about, they will likely never die.

Q: I have a nasty infestation of crabgrass in my lawn. I took the advice under the lawn care extension web site and applied a pre-emergence crabgrass granular herbicide/fertilizer in early May. It definitely did not work and the crabgrass is flourishing. What can be sprayed on it now? The areas affected are twice as large as they were last year! (E-mail reference)

A: Don't fret, we can control the crabgrass of life! Here's what you can do now. The easiest approach is to try and find a combo product that claims both broadleaf and grassy weed control - post-emergence. There are products out there that contain both 2,4-D and MSMA or DSMA which will do the job. There are products like Acclaim and Dimension that may be difficult to find at this time which would also be effective. Culturally, mow high and don't overwater. Next spring, don't use the fertilizer/herbicide combo. The AI (active ingredient) is not high enough to do an effective job. Just use the straight pre-emergent material and fertilize your lawn later, around Memorial Day weekend.

Q: My mother has a Virginia creeper vine on her porch that is under attack from whiteflies. I sprayed it down with the garden hose but am looking for a better means of control. I know Virginia creeper can be damaged from several commercial insecticides such as Sevin. Is insecticidal soap a viable alternative? How about Tempo 2? (Glenburn, N.D.)

A: Yes, you are right about all you have said. Go for it!

Q: I have a little leaf linden tree that we planted 11 or 12 years ago. I the past three years it has started to "sucker." I cut them off but they keep coming back. Is there a way to remedy this situation? (Marion, S.D.)

A: The best and only remedy available now is to cut the sucker growth back as it appears. Growth inhibitors for this purpose have been mostly taken off the market due to EPA regulations. If you can find a material that is used for inhibiting potato sprouting -- Maleic hydrazide, aka MH -- you may experience some success in keeping these vigorous growths at bay.

Q: We have a very unusual problem with our potatoes. We planted certified Pontiac reds. We like to harvest them when they are small. I dug up one plant a few weeks ago to make room for a new rhubarb plant I was given and there were two small white potatoes I didn't think too much about it until I dug up four more plants a few days ago. They are also white. I asked our county agent here and he didn't know what to think of it. They taste good . Also, some of our Ponderosa pines are turning brown beginning at the tip of branch (new growth). Some of the trees are young and some are older ones. (Dickinson, N.D.)

A: I am far from being a potato expert, but it could be that a sport or mutation has reverted back to the original form. That's the only possible answer I can come up with. Enjoy them anyway! Usually tip browning or burn in pines is an indication of backfill over the roots, salt accumulation in the plant tissue, or simply environmental stress. Take your pick -- at this point your guess is as good as mine.

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: Gary Moran, (701) 231-7865, gmoran@ndsuext.nodak.edu