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

By Ron Smith, Horticulturist

NDSU Extension Service

Q: We had a large cottonless cottonwood that we cut down. We had the tree removed and used a stump grinder to get rid of the stump. Our goal was to remove the tree and create a rose garden in its place. We used Roundup on the grass and my husband rototilled the area so we could move some dirt. In the process, he pulled up several roots from the cottonwood tree. We are getting suckers coming up everywhere. We pull them out, but more come up. Is there anything we can use on the soil to prevent more growth? We do not want to have to go to the expense of removing all of the dirt and replace it with clean topsoil if we don't have to, but it is beginning to seem that it is our only option. (e-mail reference)

A: If you can extend your patience a little longer, the growth will stop. Instead of pulling every one of them out, I suggest using a glyphosate-based (Roundup) material on the green sprouts. Eventually, you will overcome the maddening characteristic of this tree species. I don't recommend the total excavation or sterilization of the soil. There can be too many unintended consequences in addition to the expense.

Q: I have a large, split-leaf philodendron that needs some help. It gets new growth, but the edges turn brown and curl when the leaves get large. What can I do to prevent this? (Park Rapids, Minn.)

A: Browning edges are an indication of too high a salt concentration; poor aerobic conditions in the root area, such as no free drainage; or a combination of overwatering or fertilizing and too low a light intensity. Check your cultural procedures and see if one or a combination of these factors are at play.

Q: I live in central Oregon. I have a number of juniper trees that my horses decided to strip the bark off of. I am wondering if there is any hope of saving the trees. Your input on this matter would be greatly appreciated. (e-mail reference)

A: The answer depends on the age and vigor of the damaged trees. Vigorous growing and mature trees can regrow from the crown, but only sometimes. They may regrow if there is any bark or green left on the branches. If the horses girdled the trees, leaving absolutely no bark, or ate all of the greenery including the cones (a berrylike fruit), the trees probably won’t regrow. However, if the seeds from the cones pass through the digestive system of the horses, you may get some new seedlings. In all likelihood, the trees will not come back to any extent that you would want to keep them around. Junipers are tough plants and can recover from some amazing abuse, but the result is more like a Frankenstein plant than anything attractive.

Q: My Christmas cactus plant has water spots. I would like to use some leaf shine to pretty it up. Will this harm my plant? (e-mail reference)

A: I'm not a big fan of leaf shine, but many people are. Check the label to see if it is safe for using on your Christmas cactus. I would prefer you use a cloth dampened with distilled water to see if that will remove the spots. That usually does the trick without giving the plant an unnatural shine.

Q: We have received a gift certificate from our local garden center to plant a tree in memory of my wife's dad passing away. We have an area in front of our house with a south and west exposure. Our two-story house is green, so we are looking at something with good color that can handle North Dakota winters. My first choice is a fall fiesta maple tree because of its fall colors. I would appreciate your thoughts on this. The garden center indicated that it would have both bare-root stock as well as potted trees available. The purchase of bare-root stock would allow for a larger tree and at a reduced price. If you get a moment, could you see if this would be a good choice? Other suggestions would be appreciated. (Grand Forks, N.D.)

A: A very good gift in memory of your wife's dad! I would encourage you to take a bare-root tree. These get off to a quicker start and don't have the possible soil incompatibility problems with the soil it is being planted in. Planted properly and cared for the same way, you will enjoy this memorial gift!

Q: I have two Alberta peach trees. One produced 15 large peaches last year. This year, it did not produce any. Are they like apple trees that produce every other year? The main trunk split after being hit by lightning. We pulled it together and tied it up. There were a lot of little branches that had leaves this year. When and how much do you cut back the branches? (Mobridge, S.D.)

A: If your tree was struck by lightning and produced little leaves, that is the tree's last gasp! I doubt it will leaf out this spring, so you don't have to worry about pruning it at all. If it does leaf out, e-mail me when it starts. I'll gladly give you whatever information you might need. However, I suspect you will need to cut the tree off at the ground. Like apples, some peaches bear fruit every other year.

Q: We just purchased a lake home at Lake Kiowa, Texas. The property has a lot of mature trees. We were advised to cut down a mature mulberry tree, but nobody can tell us why. It is located close to the lake but does not obstruct our view. Could you please list the reasons why one might consider cutting down such a tree and what the arguments would be against cutting it down? We would hate to find out later that we should not have cut it down. I would appreciate any suggestions (Lake Kiowa, Texas)

A: Let me count the reasons why one should cut down a mature mulberry tree. The tree grows very quickly and produces an unbelievable amount of kindling wood from all the dying and dead branches. Mulberry trees are magnets for disease and insect problems. Mulberry trees are prolific producers of messy fruit that attract birds. The birds will thank you for the feast by leaving messy droppings under the canopy. A reason to keep the tree may be its historic significance. If the bird droppings are not a problem for you, then feeding them is enjoyable to watch. If your tree does not exhibit any of the negative characteristics that I listed, then you may want to keep it. Why not seek the opinion of a local International Society of Arboretum certified arborist? Go to to find one in your part of the country. That way you can make sure the only tool you need isn't just a chain saw!

Q: Can you tell me when I can start wrapping my arborvitae with burlap? I live in Michigan. Is this week too early? (e-mail reference)

A: Wrap according to the weather forecast! Michigan is a lot like my state of North Dakota. It is nice and beautiful now, but can be cold and blustery a week later. If the weather doesn't look like it is going to be closing in anytime soon, keep them as they are. If it appears that a Canadian clipper is on the way and it will sock you in for the duration of the winter, then get out there and put up a screen of burlap. However, they don't need to be completely wrapped. It will not hurt anything if you wrap them now, but with the ground not frozen and the winter winds not howling, the trees still are manufacturing food. Wrapping too early could lead to some problems down the road.

Q: I found your site and have a question for you. Is it OK to cut off the low branches of a Colorado spruce? They are on the ground and collect a ton of leaves. Thanks. (e-mail reference)

A: Absolutely! Those low-hanging branches also are hiding places for nature's furry friends, such as voles and bunnies, that crawl out and do damage to the ornamentals on your property. Skirting spruce, as this is referred to, will expose that lower trunk to allow for better air circulation and reduce hiding spots for some unwanted visitors.

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

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