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Ron Smith answers questions about flowers, trees, gardens and shrubs.

By Ron Smith, Horticulturist

NDSU Extension Service

Q: I've always respected your advice. Last week, I read your answer to a question about willow trees and how they are prone to diseases. It made me think of our willow trees. We planted two laurel willow trees in our yard about five or six years ago. They were recommended to us by the nursery because we were looking for privacy in our backyard. They grew quickly and looked very healthy. A couple of years ago, the one that we planted first started showing yellow leaves. We applied iron cleate at the recommendation of the Extension Service. It did help for a while. However, the yellow leaves came back. Also, the branches are brittle. We had a tree service inject some iron into the trunk this year, but it has not shown any improvement. The second tree started showing the same symptoms last year. Right now, the leaves are about 75 percent yellow and starting to drop. We're wondering if there is any hope for these trees or is this more than iron chlorosis? Are these trees prone to disease? If we need to replace these trees, what type of tree would you recommend? Your advice is most welcome. (email reference)

A: Since you planted these trees five or six years ago, they must be salix pentandra, which was released by NDSU. It was made available at that time through the retail market. This cultivar release by NDSU’s Dale Herman was studied extensively for 13 years around the state and was proven superior to all other accessions. The official release to growers about prairie reflections laurel willow in 2005 said, “a superior selection of laurel willow based upon 13 years of evaluating four accessions at four NDSU Research Extension Centers across the state of North Dakota. This selection originated on a farm near Brinsmade, where it flourished for nearly a century. The site was somewhat alkaline in pH, but the tree never suffered from chlorosis due to iron deficiency, which is a common problem incurred by some trees in such sites. The survival rate after 13 years averaged 90 percent. The other accessions averaged 79, 67, and 58 percent survival, respectively. Prairie reflection grows rapidly, produces a dense, rounded tree with very dark green, highly glossy foliage. It requires pruning, as do all laurel willows, to produce a single-trunked tree in nursery production. The glossiness of the leaves reflects sunlight much like a mirror, hence its name. It will reach a semi-mature height of 35 to 40 feet in 18 to 25 years and has zone 3 hardiness.” My conclusion is that the trees you have are not the prairie reflections cultivar of laurel willow, so it’s susceptible to iron chlorosis. Unless fastidious attention is paid to annual injections of iron chelate to prevent chlorosis, the trees will continue to decline until they die. You can replace them with the prairie reflections or with the northern acclaim honey locust or pekin lilac copper curls. All of them would fill the same space as the laurel willows did. Thanks for your vote of confidence with my advice. I hope this helps you in making a choice for new plantings.

Q: I have a quick question about our two autumn blaze maple trees that we planted a few weeks ago. They are about 25 feet tall and were planted professionally. About two days after planting, they turned a deep maroon-red. One of the trees also has had a slight leaf drop. We water the trees once or twice a week as instructed. Is this type of behavior normal? Any clarification or advice would help because I love these trees. (email reference)

A: Some reaction, such as fall color showing up ahead of expectations, is bound to happen. I have some questions for you to ask the nursery people. Does the nursery root-prune their stock on an annual basis to keep the roots within the ball at digging time? Were the trees watered the day before they were dug? What was the transport distance between the nursery and planting site? What time of day did the move take place? Were the trees wrapped in a tarp to prevent wind damage? Was the planting hole watered prior to planting? Were the trees set at the same depth and with the same exposure as they were at the nursery? As you can guess, all of these factors will have an impact on the trees’ establishment and survival.

Q: I need help and advice. When is the proper time and method to transplant ferns? Can it be done now? (email reference)

A: Ferns usually are best transplanted in the early spring to give them plenty of time to become established. If it is not possible to wait that long, then try to do it as soon as possible. Water the fern thoroughly the day before the intended transplanting. At the new site, work in plenty of organic matter, such as peat moss, and then dig the hole and water. Wait until evening to do the transplanting. This will cut down on water loss and be less stressful to the plant if moved when the sun is setting and the temperatures are cooler. Take as large a root ball as possible to minimize stress. Once planted, water it in completely and make sure it never dries out before freezing this fall. If you wait until spring, the same routine would be recommended.

Q: For a few years, I have had two large ant mounds on my lawn. I've tried a few ant remedies, but they didn’t work. The ants have killed the grass around the mounds. They are stinkers about having the grass mowed around the mounds and have made their irritation known! I would appreciate any input. I like the idea of not using poison, but I’m also a realist. (email reference)

A: It sounds like you have an aggressive colony of ants that don’t want to be disturbed. Never underestimate these little creatures. They’re incredibly smart and well-organized in their objectives. Human inconvenience is a nonissue with them. They are very difficult to eliminate unless you get some poison food that they will take to their nest. What is available for the homeowner may or may not work. I’m no ant expert, but I know enough that different ant species require different treatments to get rid of them. If possible, I would recommend that you hire a professional to do the job. You can try boric acid mixed with sugar. The ants consume the meal and then die. If you are brave enough, you can use a bucket of boiling water to flood the colony. You need to do this in the evening when they are all in the nest. A repeat application might be needed if the colony is very large.

Q: We excavated our backyard to install a brick patio. In doing so, the machinery cut through many roots of a mature ash tree and a Norway maple. Will this kill the trees? What should we do to protect them? (email reference)

A: So much depends on how much of the root system was destroyed, the vigor of the trees and your environment. If the excavation work was done by a landscape contracting company, I hope the people in charge were somewhat surgical in the removal of the roots. That, too, would have an impact on the survival of the trees. There are a couple of actions that are possible to help the trees survive. Get in touch with a certified arborist to help you save the trees. Arborists differ in their skills, so describe what your concern is so that you don't waste your time with someone who doesn’t have expertise in this area. You also can contact your local Extension Service agent. If the agent can’t help, he or she can connect you with someone at the land-grant university in your state. It is important that you have the situation checked out because trees with damaged roots have the potential to fall over during a storm.

Q: I have an apple tree in my yard that lost all its apples the last few years just before the first freeze. This year, I’ve noticed that the bark on the tree is peeling. Do you have any suggestions about saving the tree? My wife wants to cut this beautiful tree down. (email reference)

A: You might have an early maturing variety that ripens without any significant cold required for sweetening. If not, then all I can suggest is to try fruit load control by picking some of the apples in June while they are marble-sized. Removing 25 to 30 percent of the apples at this stage often results in the remainder developing to normal size. Another reason for premature apple drop might be associated with insect damage from coddling moths or apple maggots. You didn’t say whether you consumed the apples or if they had damage from either of these pests. Bark peeling on a mature apple tree could be normal for the cultivar or the result of excessive moisture from the very rainy summer we’ve had. In either case, it is nothing to worry about.

Q: I was reading your website about hostas plants and noticed a question about deer nibbling on the plants. I have had success at keeping the deer away using mothballs. I use old vitamin plastic bottles with holes punched in them and filled with mothballs. I place them around the hostas, roses, sedums, spring bulbs and anything else the deer love to munch. I haven't lost anything for years. I assume the deer must hate the smell. For some reason, all the people I know that complain about deer eating their plants will not try my remedy. This solution works for me and might help others. (email reference)

A: Thanks for writing about your experience with mothballs. It used to be something I recommended. However, someone from the Environmental Protection Agency told me such use of mothballs was illegal and dangerous and that I should cease making recommendations for such use. You might want to read the information at before handling or using mothballs again in this manner. You might want to read a publication from the Natural Resources Conservation Service about other methods of controlling deer predation. You can find it at

To contact Ron Smith for answers to your questions, write to Ron Smith, NDSU Department of Plant Sciences, Dept. 7670, Box 6050, Fargo, ND 58108-6050 or e-mail

NDSU Agriculture Communication – Aug. 31, 2011

Source:Ron Smith, (701) 231-7971,
Editor:Rich Mattern, (701) 231-6136,
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