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Ron Smith answers questions about plants, trees and gardens.

By Ron Smith, Horticulturist

NDSU Extension Service

Q: I have three lovely Lombardy poplars in my backyard. I know you detest the suckers they send out, but I want to transplant some of them to start another row of shade trees. Can you tell me how to do this? I've had no luck in the past. (e-mail reference)

A: Generally, sucker transplants don't work too well because they don't have an independent root system as seedlings do. So prepare to fail and be surprised if they do make it. Dig up the smaller suckers with as much of the root from the mother tree attached as possible. Plant the trees this fall after they go dormant. The hope is that the trees will have the maximum amount of carbs stored within to re-establish themselves next spring. Water them well after planting. When the frost comes out of the soil next spring, water the trees to keep the soil moist, but not soggy.

Q: I have a question about a large willow tree on my property. This tree was planted too close to my house. In the last few years, I have noticed that its roots have come through my sump hole and might be in my foundation walls. I want to kill the tree before this problem grows. I have someone who is going to cut down the tree, but I realize this won't completely kill it, so the roots will continue to sprout. I don't think the stump can be removed because it is too close to my house. I’m afraid that taking out the stump with the roots intact will affect my foundation. Is there a way to kill this tree without removing the stump? (e-mail reference)

A: Usually, an arborist is knowledgeable about killing stumps and tree removal techniques. I've had to remove trees using a pickax or stump grinder. The trick is to get below the soil surface to take out as many roots as possible. This usually works. Being too old to swing a pickax anymore, I’d hire someone to do it, which doesn't do you a bit of good! Here is a Web site - - with information on a product that is recommended for the job. I never have used it, so I cannot give it any recommendation one way or the other. However, knowing the reputation of the company and the explicit instructions that accompany the material, it sounds like it should do the job for you. Best of all, it is legal and relatively safe.

Q: I had a lawn care service come to my home while I was gone. It significantly trimmed my old dogwoods. I am upset and afraid this will kill them. I don't even let my boys play on the dogwoods, so I was crushed to find them so mutilated. The trees are native white dogwoods. I cannot believe anyone would do something like this. I live in northern Louisiana. Please tell me the best avenue to take to save them. Their limbs went to the ground, so I had the people who did all the damage put pine straw under the trees to protect the roots from direct sunlight and add acidity to the soil. Should I paint the wounds with black pruning spray? What should I do to help them live after this brutal pruning? (e-mail reference)

A: I hope you communicated your dissatisfaction to the folks who did the pruning as you just did to me. They need to get the message! Don’t do anything to the trees. Tree wound paint only complicates things. If they are otherwise mature and healthy trees, they will recover from this mishap with flying colors. Don't fertilize and don't get into overwatering. Let Mother Nature take charge because she usually pulls plants through these human-made traumas.

Q: My son thinks he has rabbits eating the wood siding on his house. Do rabbits do this? I never have heard of it. What can he do to get them to stop? I raised rabbits as a child and never saw them chew on anything except their salt wheel. (e-mail reference)

A: I really doubt rabbits are the problem. I had rabbits on my farm in upstate New York in another life. In spite of their other antics, I never saw them do something like that. If your son gets some commercial pepper spray and applies it around the area where the chewing is evident, it will stop unless the critter has a love for hot foods!

Q: We had a creeping juniper in front of our home, but had it taken down after 22 years of growth because it was woody and yellow. Can you suggest a way of removing the root system? Can we cover the roots with a foot of topsoil? Will this prevent future growth? (Ottawa, Ontario)

A: The roots of a juniper seldom resprout, so that should take care of the problem. Any growth that does pop up can be controlled with a touch of Roundup.

Q: I recently had six arborvitae trees planted next to my fence for more privacy. The trees are planted as close together as possible, but there are gaps on top. Should I tie the tops together to close the gaps? I watered and used Miracle-Gro on them. Any advice on what to do to get them through a New England winter would be appreciated. (e-mail reference) A: The gaps will close with time. Don't tie them together or you'll end up regretting it. You can cut off your watering because the trees need to toughen up a little for winter. If they are facing a southern or southwestern exposure, I would suggest putting a burlap or mesh screen in front of them to keep the sun from desiccating the foliage. Don't wrap them in burlap because that may be a good precursor to disease development.

Q: I have two Christmas cacti that are between 20 and 25 years old. One belonged to my mother and the other to my grandmother. They are kept in the same room, so they receive the same amount of sun, temperature and humidity. I water the plants about every 10 days. One looks great. It is dark with strong joints and blooms three or four times a year. The other plant is weak and pale. The sections are wrinkled and withered. I've looked at the roots on both plants and they look the same. The only difference I can find is that the healthy plant is in a small pot, so the roots are more bound. Should I try putting the other plant in a smaller pot? Do you have any other suggestions? Thank you for any help you can give me. (e-mail reference)

A: You have nothing to lose by attempting to put the plant in a smaller pot, but it doesn't sound like the plant will make it much longer. I have no other suggestions to give you. Give it a try and hope for the best!

Q: I have two variegated ficus plants that have brown spots on the leaves. I sprayed the leaves with a fungus spray, but brown spots remain. What should I do? Also, I have a Chinese fan palm plant that I purchased last year that’s not growing at all. Should I repot it? How do I get it to grow? Can you recommend a good type of indoor palm plant for my home? (e-mail reference)

A: If it is a fungus that is established on the plant, spraying with a fungicide almost never cures the problem. The leaves that have spotting will continue to have it. Try to adjust the environment around the plants to get more light, air circulation or lower humidity. Actions like this usually are more effective at arresting the fungus than most topically applied fungicides. Chinese fan palms are not known to be rampant growers as houseplants and don’t require much care, so they are popular in commercial settings. I would suggest being patient as long as the plant is otherwise healthy. Give it the care you would of any other houseplant. Consider a parlor palm (Chamaedorea elegans) as a good selection. It is one of the better low-light-tolerant houseplants.

Q: I have a row of Amur maples that I use as a boundary. Most are healthy, beautiful trees. However, one or two of the largest trees are showing signs of dead branches in the center. Should I prune these out? Is there a typical age when Amur trees tend to die? (Monticello, Minn.)

A: Go ahead and prune sometime late this winter or in early spring before the tree leafs out. If there is a typical age when the trees die, I don't know what it would be. I have had mine for more than 22 years. It is thriving and beautiful. Given normal, good care and monitoring to catch minor problems before they become major ones, you will be able to keep the trees around for as long as you want.

Q: I have birds nest spruce trees that are thin and woody under the top green level. How do I get them to come back? Also, my emerald mound honeysuckles are large shrubs and very woody. I have a top layer of leaves that I pruned, but how far can I prune the shrub back when all the rest is very woody? (Traverse City, Mich.)

A: Bad news for the spruce. They won't come back and there is nothing you can do about it. Sorry! There is better news for the honeysuckles. Prune them back to the ground now or early next spring before new growth comes out. They should send out a flush of nice, vigorous and healthy leaf growth.

Q: I have a question about my healthy ficus. My concern is that my tenant planted it in our cement planter, which is part of our cement patio. I am afraid that as it grows, it will crack the cement planter and the patio. Do you think this is a possibility? If so, could I remove it and replant it in a pot for use as an indoor plant? (e-mail reference)

A: Eventually, the pressure is going to get too great in a confined space, so it will crack the planter. When the plant is not actively growing is the time to transplant it into a separate container and use it as an indoor plant. The other alternative is to dig it up once a year. If you do that, you will need to trim the roots and then replant it using fresh potting soil. The plant always will do better as an outdoor plant.

Q: Years ago, I planted a young pear tree. As it grew, all of its branches went straight up. I finally decided I'd better correct the problem. I staked all the branches that I felt needed to be staked to spread them out. I left them that way for two years. They turned out beautifully. I then pruned them according to the crossing branches theory and the next spring I had one beautiful blossom. Later that summer, a small pear grew. The pear wasn’t very good, but it was a victory as far as I was concerned. Now I've had my first full season as a pear tree farmer. From this small tree, I've gotten around 75 to 100 pieces of fruit. Most of the fruit was as large as a good-sized orange. They taste good and are not ripening and spoiling like my other tall, expansive tree whose fruit spoils right away. I've looked up information on pear trees to follow the proper procedures in caring for my two trees. I have no idea as to what type of trees they are. Every year it gets better. Thank you for all that you do and I am so envious as to what you have at your hands and in your head. You truly are a phenomenon. (e-mail reference)

A: Thank you for your exceedingly kind words! I am not a phenomenon by any means. I’m just someone who tries hard and has made a lot of mistakes during a long life, but who continues to learn every day. I'm glad your pear tree now has made you an official "pear farmer." Enjoy!

Q: My daughter brought a Norway spruce home from school. The landscape of our property will not tolerate a large tree. I've suggested that we plant it in a large outdoor pot. Will it survive as if it were planted in the ground? (e-mail reference)

A: If the plant will be in North Dakota for the winter, it probably won’t survive. The root system has a higher lethal freezing point than the aerial system of the plant. In other words, the branching system of the tree is hardy to minus 30 degrees, but the root system only to zero. Exposure to a subfreezing temperature for any length of time would kill the plant unless it was very well insulated or plunged into the soil, pot and all, for a few years.

Q: My question is about my grandmother's snake plant. She died 13 years ago and I inherited it. I placed it in a south window and didn't do much to it for a long time. I was amazed to see it flower several times in the middle of the winter. It did that sporadically through a five-year period. I didn't even know it was possible! When the plant started bursting out of its pot about seven years ago, I made what I believe was the awful mistake of repotting it into a larger pot. It never has been the same. It sort of hangs in there, but it is sad, yellowing and leaning. I don't want to let this plant die because it is very special to me. I'm wondering if there is anything I can do to bring it back to its glory. (e-mail reference)

A: The poor plant probably has had it with low-light environments. These plants are killed more often by kindness, such as overwatering and fertilizing. Snake plants are best off just being left alone. It also could have something to do with your watering cycles. In the smaller pot, the plant probably got along on your watering regime. In the new, larger pot with a greater soil volume, the same watering cycle would be too much and bring about the symptoms you describe. My suggestion is to move the plant where it can get more indirect and stronger light. You could use a plant light. Hold off on the watering. If you think it needs watering, wait at least a day before doing so. I never have known one of these plants to die due to underwatering. Finally, take some cuttings from the leaf tips and root them. Actually, the cuttings will not root, but will send up new plantlets from the vascular tissue within the leaf. Hope this helps and good luck!

NDSU Agriculture Communication

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