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Ron Smith answers reader's questions about the world of plants and gardening.

By Ronald C. Smith, Horticulturist NDSU Extension Service

Q: What would be a good choice for a low-maintenance, perennial ground cover for an area that receives limited direct sunlight and is in a somewhat drought-prone area of southwestern North Dakota? The soil is somewhat compacted. I would prefer prostrate/semiprostrate growth. If the growth is upright, then I'm looking for a cover that is short (less than a foot tall). Also, what would you suggest for a tall-growing, ornamental perennial grass that only receives morning sunshine? (Dickinson, N.D.)

A: Thanks for some easy questions! There are no "good plants" that I know of for the situations you describe. However, you might want to consider liatris, sedum and sea thrift (Armeria spp), but I make no guarantees. As for the grasses, try a species of miscanthus sinensis, feather reed grass - calamagrostis stricta or switch grass - panicum virgatum.

Q: We have had a persistent problem with some creatures around our front walk and brick work. I thought they were millipedes, but someone told us they are centipedes. They are about an inch long and curl up when in distress. They have hard shells and are driving us batty. We have to go out and clean them up every morning or else step on them, which leaves a permanent imprint in the concrete. Normal insecticides control them temporarily, but they always come back in force. Some of the sprays we used indicated they would control millipedes, but were not really effective. Any suggestions? (West Fargo, N.D.)

A: I had the same problem when I moved into our home 21 years ago. I called Johnson Pest Control for help. It sprayed with an approved insecticide and I haven't had a problem since then! I suggest contacting Johnson or some other licensed pest control company. These companies are licensed to handle restricted-use insecticides that are not available to the homeowner.

Q: We are trying to figure out if our silver leaf maple produces pollen. We live in Colorado, where the weather has been quite warm for a couple of weeks. The tree has thousands of budlike brown clusters that look like flowers, but they're hard. They're littering our entire driveway. Do these buds mean the tree is a male and produces pollen? We also have read that female trees produce small seed pods, which I am pretty sure our tree does not. My husband is having allergy problems because of the pollen. (e-mail reference)

A: Unfortunately, the answer is yes. These trees do have the potential to produce pollen. The flowers on the silver maple are referred to as being monecious, which means there are separate female and male flowers on the same plant. If the trees are seedling selections, they tend to sort out as either predominately staminate (male) or pistillate (female). If cloned selections are made by the nursery, then the tendency would be to select trees that are male (nonseed producing), unless the seeds of a particular tree are extremely ornamental and have high market potential. As far as I know, there is nothing on the market that could be practically applied to control the pollen production. I don't like your husband suffering this miserable allergy, but I also don't like the idea of removing an otherwise perfectly healthy, beautiful tree. Any chance there is some benign medication he can take during the brief pollen-producing season?

Q: I love hollyhocks, but I have three dogs that dig up the roots and eat them during the winter months. I didn't pay much attention until this morning, when one of the dogs had some kind of a fit. I was wondering if the roots are like a vitamin supplement during the winter, but have a nerve toxin during the spring. Thank you so much for any help you can give me. (e-mail reference)

A: None of my poisonous plant books list hollyhock as having any toxic principles, but that doesn't mean they are harmless. It could be there have been no reported cases of poisoning from this species. I would contact a veterinarian at New Mexico State University's Extension Service to see if he or she can provide you with additional information.

Q: I have a local resident that has a question about her African violets. She transplanted them back in December 2005. Since then, the plant has not bloomed. She now has a few blooms on a couple of plants. She switched from well water to rain and snow water. While using well water, a crusty, white residue was appearing on the bottom of the pots. She is so frustrated that she admits to throwing away some of the plants. She is seeking your help before she throws all the plants out the door. (Griggs County, N.D.)

A: She should not have used well water. African violets are raised on pure rainwater in their native setting, so she should stick to the rain or snow water to get the plants blooming again. She also needs a dose of patience. Blooming, which is the reproductive cycle of any plant, requires stored energy. Insufficient energy equals poor or no blooms. When they get to that point of sufficient energy and mild stress, they will bloom. African violets should not be thrown out the door, especially in North Dakota!

Q: I have a lilac bush and need to know when and how to take cuttings. (e-mail reference)

A: When you use the term cuttings, I take it to mean that you want to carry out propagation. If that is the case, you should know that lilacs are not easily rooted from cuttings, so timing is very critical. Softwood cuttings work best and should be taken before the leaves mature. The cuttings will need to be treated with a rooting hormone and placed in a sand or vermiculite medium. For watering, use an intermittent misting system. If you are talking about just pruning the plants, there are a couple of options. If you prune while the bush is dormant, you have to realize that each stem you remove will reduce the number of spring blooms. The other option is to wait until blooming has ended, then do the pruning before new growth emerges and has a chance to set flower buds for the following spring.

Q: I have a maple tree and want to plant another one, but I don't want to purchase the new tree. Is there is a way to take cuttings or something from the tree I have? How and when should I do it? (e-mail reference)

A: Your question is too vague to give you a focused answer, so I'll give you the options. Maples are monecious, which means there are separate sexes on the same tree. Some trees are predominately male or female in flower production. If the tree you have is a silver maple that produces an abundance of seeds, they will germinate shortly after planting. If your tree doesn't produce much or any seed, then the flowers are male and you would need to propagate the tree through softwood cuttings after the leaves come out, but before the new growth hardens off. There are some 50 known species of maples. Each species has its own twist as to how it should be propagated. Some seeds need stratification for 90 days at 41 degrees in a moist peat moss. Some root readily in the same manner as the silver maple, while others take considerably longer with a much lower success rate. Most homeowners lack the facilities and patience to do this type of propagation, so I would advise you to buy another tree. You can get one in a 5- or 10-gallon container that will take off quickly and provide you with shade and landscape impact in a short period of time.

Q: I have had a problem getting things to grow in my garden since I moved here in 1999. The previous owners had the same problem. I live close to the Bois De Sioux River south of Wahpeton. The garden is surrounded by trees on three sides, but it has full sun until very late in the afternoon. The closest trees are about 25 feet away on the north side. I had a soil test done in 2001 that showed everything was great, except I had no nitrogen. I starting tilling in grass clippings and leaves for organic matter, but was told it depletes the nitrogen. I added nitrogen every fall, which seemed to work for a couple of years. Last year I was back to the same problem of things not growing, so I did another soil test. This time I had too much nitrogen and dissolved salts. The garden has decent drainage, but I hauled in two truckloads of dirt to help with drainage. Could having my garden right next to my septic system drain field be affecting the dissolved salts? I installed the septic system in 2000. At my previous residence, I always had a lush garden and did all the same things I have done with this garden. What can I do different or do I need a different location? Gardening has always been relaxing to me. However, when you can't get anything to grow, it gets to be a waste of time and adds more stress because of the frustration! Thanks in advance for your help! (e-mail reference)

A: The high soluble salts definitely will create a problem in trying to grow vegetables. The septic system is a major source of your problem. If the salts cannot drain away, they accumulate in heavy soil and cause problems with seed germination, subsequent growth and the production of a harvestable crop. Many gardeners are finding success with raised bed/square-foot gardening. They are above the surrounding soil and create their own "designer soil" with good drainage and low salt content. You also can tweak the nutrient levels to suit the crops being grown. I would suggest this as an alternative or moving the garden to another location away from the septic field.

Q: How far would I have to move it away from the drain field or could I raise the bed where it's at? I have a 1 1/2-acre yard, but my options are limited as far as location. (e-mail reference)

A: Put together some 1-foot by 6-foot planks and bring in some fresh soil. If you are going to grow root crops, use 1-foot by 12-foot planks and keep the garden where it is now.

Q: We planted a new lawn late last fall. My husband is wondering if he could drag it again this spring before it starts coming up. He thought about adding more grass seed, too. What do you recommend? It did not sprout last fall. (Carrington, N.D.)

A: You will get some germination this spring. Assuming it wasn't old seed, the seed that was put down went through a priming process this winter and should sprout with a vengeance this spring. I would suggest waiting to see what comes up and then overseeding the bare spots. The whole purpose of fall seeding a new lawn is to give the slower germinating Kentucky bluegrass a chance to be competitive with the millions of weed seeds that are present. I'm afraid that if you reworked the soil this spring, the lawn seed that was placed last fall will get buried too deeply and only the weed seed will sprout!

Q: I adore the fragrance of lilacs and hyacinth. I had lilacs on the side of our house in Indiana as a child. I now live in San Diego. I am in a condo with front and back patios. However, my patios are not at ground level, so I need to grow plants in a pot. Can these flowers grow in that format and will they do well in Southern California? I never see them growing around here, especially lilacs. (e-mail reference)

A: Sorry, you are out of luck. Lilacs and hyacinths need cold treatments from Mother Nature to grow and produce flowers. You could move to North Dakota, where we occasionally have cold weather that brings the lilacs and hyacinths into flower!

Q: We have a mix of yellow jackets and other types of wasps in my backyard and around the house. Some are black and some are hot red. I have been hunting them down, but I think most of the wasps are behind the siding of the house. My house has three levels, so getting to anything over 13 feet is out of the question. I had a professional look at the problem. I was told the siding would have to be removed to find each nest. I also was told there is no way to make them leave on their own or keep them from coming back after they were removed. I have been putting small bird houses around the backyard and house to see if the birds would cut the number of wasps flying around. I have four to six bird nests around the house and some bird feeders to attract more birds. I have a lot of birds, but I have not seen a reduction in wasps. (e-mail reference)

A: From what I know about your situation, the professional is right on the mark. A neighbor of ours had the same problem. Wasps were nesting under the siding of the house at ground level near the kitchen door. Like you, the neighbor tried everything possible to get rid of them. The neighbor finally resorted to having a professional remove the siding to get a complete kill. If I knew of another alternative, I certainly would let you know. If any readers of my column come up with some sane solutions, I'll pass them on to you!

Q: We planted a weeping willow late last summer. While we were gone on vacation, it got hotter than we expected. Some of the leaves turned yellow and fell off. We are coming into spring now here in southwestern Wisconsin. The tree made the winter with a nice yellow color on the trunk and halfway out each limb. Some limbs are completely brown, while some limbs show small buds halfway out the limb. Do I cut the limbs back to where the buds stop? Do I cut the limbs without buds at the trunk? (e-mail reference)

A: Go for it, before the heat, humidity and bugs make cutting the limbs a real chore!

Q: Am I better off to prune a limb that is partially budding at the trunk or out at the point where the limb is brittle? Will the tree sprout a new limb at the trunk or will the branch continue growing if I cut the limb where the buds stop growing? (e-mail reference)

A: Dead wood is dead and no amount of pruning will revive it. If you prune a live branch back to the trunk, you may or may not get a new branch at that point. Willows are loaded with latent bud and root initials under the bark, which gives them the advantage of being extremely easy to root and form new branches. If you cut back to a visible live bud and remove the dead tissue, that bud will break dormancy and grow as a dominant bud. In reality, as your tree matures, you will be spending a significant amount of time walking around the tree picking up the self-pruning it will produce. Your future pruning tasks will be to keep it in some semblance of shape to enhance your property.

Q: I had someone in the office with a garden supply catalog that sold red-colored tomato accessories, such as red wall-o-waters, red root zone waterers and red mulch. Is there any research about the successful use of these red products or is it advertising hype? (Ward County, N.D.)

A: Research years ago using red plastic mulch under tomato plants reported an increase in production. We tried to duplicate that at the Dickinson Research Extension Center, but did not find that to be true. There is probably a nugget or two of truth, but I would say the hype outweighs the truth somewhat. The successful research used red plastic mulch and drip irrigation, but nothing else.

Q: We have a dogwood in our backyard that was beautiful two years ago when we moved in. About a year ago, the neighbors had a pine tree cut down that was very near our dogwood. Part of the pine tree fell and broke one of the biggest branches of the dogwood. We made a clean cut where the break occurred, but since then the tree has been in distress and other branches have been dying. Now, at the beginning of spring, only one branch has flower buds. What should be done? Is there any hope of our dogwood surviving? Additionally, we have six dogwoods in the front yard that are full of buds, except one. There has been no known damage to the tree. What could be wrong? Any advice you could give me would be very much appreciated! (e-mail reference)

A: There is no hope for the dogwood that was damaged by the falling pine branch. The problem with the tree that is not budding could be borer damage, stem cankers, root rot organisms, an abiotic cause of death, girdling by rodents, a saturated root zone or environmental exposure. Only a close inspection by someone knowledgeable about plants can determine the actual problem.

Q: I've read your articles for a long time. I live in Fargo and I am wondering if it is too late to prune my apple trees? Also, some of my apples last year had what looked like a worm trail through the apple, but no visible hole on the outside. Is it a blossom fly/maggot and how do I treat my trees? I have golden delicious, Macintosh and Haralson apple trees. The Macintosh did not seem to have any infestation. The problem occurred in a few of the apples, not all of them. (Fargo, N.D.)

A: Thanks for being a faithful reader of the column! It is not too late to prune your apple trees. In fact, now is a perfect time. Pruning anytime before the tree leafs out is good. The insect damage probably was caused by an apple maggot. Eggs are laid by female flies in the developing fruit through holes they puncture in the skin. The larvae that hatch from the eggs then make their way through the flesh of the apple, leaving the trails you saw. To control this pest, there are a couple of options, such as using pheromone traps or sticky fake apples, or spraying with Sevin insecticide around Memorial Day weekend and about every 10 days thereafter. Be sure to pick up any dropped apples because that is where the pests emerge and pupate in the soil until spring growth begins. I would suggest going with the nonchemical methods this year to see how effective they can be. I'm not a big fan of using a lot of sprays on backyard produce, unless there is no other effective alternative.

NDSU Agriculture Communication

Source:Ron Smith, (701) 231-8161,
Editor:Rich Mattern, (701) 231-6136,
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