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

By Ron Smith, Horticulturist

NDSU Extension Service

Q: How do I maintain and cut daisies? I have a path that has grown wild with daisies that hang over the pathway. (e-mail reference)

A: This is almost like asking me how to eat chocolate chip cookies. The answer is any way you can! There are Shasta and African daisies, with the Shasta being a perennial in most parts of the country. They grow and grow and have abundant flowering. I suggest that they be cut back or deadheaded at the end of the flowering cycle. After the foliage dies, I set my lawn mower on the highest cutting level and mow them down knowing that they will come back next year without any problems.

Q: I have a hybrid poplar that has three branches attached to the trunk about 2 1/2 feet from the ground. Can I cut them off? Will the point at which they attach to the trunk move higher as the tree grows taller? Does this encourage more vigorous branching higher up? The leaves on the lower branches tend to be half the size of those higher up the tree. (e-mail reference)

A: You can trim those lower branches off without any problems. The point at which they are attached will remain at that level for as long as the tree lives. It only grows from the terminal bud of the tree. It is better to get the branches removed before they get beyond the hand pruner or lopper stage for removal because a smaller wound will heal and compartmentalize much faster.

Q: I have a home that I took over from my parents that has arborvitae trees around the perimeter of the backyard. They were planted about 35 to 40 years ago. I’m getting a little worried because they are getting a little brownish here and there. Is this normal? I’ve noticed my neighbor’s arborvitaes doing about the same thing. I live in Massachusetts. It was a dry summer and winter is just around the corner. Without these arborvitaes, my backyard would not be the same because I would lose all the privacy. (e-mail reference)

A: This is normal for trees that old. If there was drought stress this past summer, it would be pushed a little, but still nothing to worry about. The trees have been there for a long time, so the root system is quite extensive and far-reaching. If it would make you feel better, get a soaker hose and place it outside the spread of the branches and give them a good soaking for four hours if the autumn rains seem to be insufficient. Whatever you do, don't spray them with any anti-desiccants or try to fertilize them at this time.

Q: What an informative Web site! I hope that you can help me. Two years ago, my husband and I planted five apple trees. All five are different and all are blooming in the fall. What in the world is going on? I live in southeastern Ohio and never have heard of this problem. Can you tell me how to get the trees back on track? Any help would be greatly appreciated. I can't find any information on this problem. (e-mail reference)

A: This is just a very occasional phenomenon that takes place with fruit trees. The cold requirements for flowering apparently were met earlier this fall with a frost or low- temperature period that satisfied the low-temperature requirements. I wouldn't worry about it because the trees eventually will adjust back to flowering in the spring and produce a nice apple crop. There is nothing you can do except be patient and wait for nature to make its adjustments.

Q: I was hoping you could answer my question about a river birch I bought from a local hardware store. It came with little information. The tag says it’s a river birch, but doesn't say what variety. It appears to have only one trunk. I wanted one with multiple trunks. It looks like branches are forming at the bottom of the tree. Do I need to do anything special to form multiple trunks or will they form on their own? The picture on the tag looks like it just has one trunk. I have read on the Internet that I could plant multiple trees together to form multiple trunks. I've also read they will form on their own and not to clump the trees together because they will not form a strong trunk. I am very confused at this point. I would appreciate it if you could help. (e-mail reference)

A: It is interesting reading about all the options you found to form multiple trunks. I was taught a long time ago that the best way to form multiple trunks is to tightly plant three saplings close together. From everything I've seen during the many years of my life as a horticulturist, that idea seems to work. The saplings intermingle their roots and from natural grafts among the trees to form a very solid union. As to the other methods you mentioned, I don’t know, so I'm afraid you are on your own in those areas. River birch is a beautiful tree as a single trunk, as most birches are, so I wouldn't fret too much if you cannot find two more to plant with the one you have.

Q: My daughter was cutting weeds beside the garage and accidently cut off my lilac bush. Will it come back next year? (e-mail reference)

A: I really can't say for sure because I don't know what condition it was in. If it was healthy and vigorous, it very likely will grow back next year. It certainly is worth waiting to see if anything emerges next spring.

Q: What is the most colorful maple tree? I planted fall fiesta maples last year. Was that a good choice or should I have purchased autumn blaze? I live in Sioux Falls, so I hope the fiestas do well. Also, I have heard that silver maples tear up concrete. Do autumn blaze maples do this also? (e-mail reference)

A: Fall festival is a cultivar of sugar maple, while the autumn blaze is a cultivar of the red maple. I have no personal experience with fall festival maples, but, according to my references, it sounds excellent. I'm betting you made a good choice. As for your question about the tree tearing up concrete, any large tree species will cause sidewalks to shift if they are planted too close. The air/water balance is conducive to root development under them. This includes, but is not limited to, American elms, poplars and all large maples, such as silver, sugar, Norway, oak and hackberry.

Q: A lady called who has several oak tree seedlings her son started in foam cups. Should she attempt transplanting them outside at this time? (e-mail reference)

A: You bet! They need to get conditioned to the upcoming winter weather. Have her carefully split the cups and place them with the seedlings at the same depth. I'd also suggest building a chicken wire fence/canopy over them. After the plants defoliate this fall, pack the plants with fallen leaves. The leaves will protect the seedlings from wide shifts in temperature. The chicken wire will keep rabbits and other rodents away.

Q: I have a maple tree on my lot that flows with sap in the spring and fall. Is there a problem with this tree that I should be concerned about? It attracts many large bees and flies. Is there a way to stop this natural flow without damaging the tree? (e-mail reference)

A: This is slime flux, also known as wet wood. The sap is a foul-smelling and unsightly seepage from the trunk of a shade tree. It occurs in apple, birch, elm, hemlock, maple, mulberry, oak, poplar and willow trees. This disease usually is not a serious problem if the tree is otherwise healthy. Slime flux is a bacterial disease. The infected wood frequently is discolored or appears water soaked (wet wood). Gas (carbon dioxide) is produced by bacteria fermentation. The gas produces pressure in the wood that forces sap from the trunk through cracks in branch crotch unions, pruning wounds, lawn mower wounds, other injuries and, occasionally, unwounded bark. This oozing of sap is termed fluxing. The flux is colorless to tan at first, but darkens when exposed to the air. As fluxing continues, large areas of the bark become soaked. Many different microorganisms grow in the flux and produce a foul or alcohol smell. Various types of insects are attracted to the slime flux. If the fluxing continues for months, leaves on affected branches may be stunted and chlorotic. Grass may be killed where the flux runs down the trunk onto the grass. Sap may continue to ooze for several weeks or months, but usually stops without treatment and doesn’t damage the tree. Slime flux may be triggered by heat, drought or other stress. There are no curative or preventive measures for slime flux except to maintain trees in a general good state of vigor and minimize wounds and injuries. More damage can be done to the tree by attempting to cure slime flux than the flux will do alone. It has been a common practice with slime flux on American elms to drill a hole in the trunk and insert a pipe, which does not cure the problem. Inserting a pipe only allows the sap to drip on the ground rather than run down the trunk. This practice is no longer recommended because it does little good. If there is loose or dead bark in the slime flux area, remove all of the loose bark and allow the area to dry. Do not apply a wound dressing.

Q: I planted 18 green giant arborvitaes last fall. They did well and seemed to be established. All 18 grew at least a foot and were a beautiful green. In late summer, 10 turned brown, three are green (as expected) and the others are brown with some green foliage. I have a year warranty (that ends very soon) on the trees and do not know whether I should replace the ones that are brown. I live in North Carolina and this summer was very dry, so I occasionally watered, but not daily. Can you provide any insight or advice to determine if my investment has died? (e-mail reference)

A: It doesn't sound like some of the arborvitaes are thriving, so I would contact the landscaper to have those that are brown replaced. Even if the cambium is still green on parts of the branches, making them technically alive, I still would insist on replacing them. Who wants dead-looking evergreens on their property?

Q: About five years ago, I had a volunteer cottonwood come up a few feet from my foundation. It also is very close to being on top of my gas line to the house. It is now 30 feet tall. I had no idea what kind of a tree it was until now. I went to your Web site to determine the tree type and if it is a problem being so close to the house. Now that I know it is a cottonless cottonwood, I have a decision to make. Can you help? It gives great shade, but I've been reading about what a nuisance they are. Can it damage my foundation? What would you recommend? Let it be or remove it? What would be the best method of removal to prevent suckers from coming back? (e-mail reference)

A: I would suggest getting an International Society of Arboriculture certified arborist out to inspect the tree and do some selective pruning to remove any potentially dangerous limbs that may come down on the house. While the arborist is at it, I would suggest that a soundness test be done. This determines if the interior of the tree is rotting out or not. If it is, then there is a good chance it will need to come down. As for the foundation, if it isn't leaking, then it shouldn't be a problem. Typical roof overhangs keep the soil dry enough that roots don't develop vigorously in that area. For the moment, your main concern should be with the top of the tree, not the roots.

Q: I received English ivy as a gift and have it sitting on a glass table. I noticed when I was cleaning that the glass was coated with clear, sticky syrup from the plant. Is this normal for this kind of plant? Will it drip if I hang it? (Jamestown, N.D.)

A: This is not normal! Look closely at the undersides of the plant to see if there is evidence of spidermites. If they are there, you will see fine webbing and specks about the size of a period in a sentence. They insert their stylet mouth parts into the plant tissue and extract carbohydrate-rich liquid and excrete it. If the plant is small enough, get some Safer's insecticidal or miticidal soap and dip the foliage in the solution to eliminate the pests. If the plant is too large to do that, spray the foliage with the same solution, but concentrate on the undersides of the leaves.

Q: I have three beautiful pots of impatiens. Is there a way to keep them alive and healthy through the winter? It gets very cold and snowy, so I can’t keep them outdoors. (e-mail reference)

A: About the only way I can think of is with supplemental plant lighting and misting while the central heating system is in use. No guarantee of success, but it is worth a try! Let me know if they make it.

Q: I changed jobs, so one of my clients gave me a great-looking jade plant, but the trunk is partially laying on the top soil. Also, there is a spider plant growing in the same pot close to the jade trunk. I have been reading and learning a lot on your Web site, but I haven't seen any similar problems listed. Any suggestions would be great and thanks much! (e-mail reference)

A: I would suggest diligently separating the two plants and giving each its own pot. If you lack the confidence to do this, see if you can find a local florist to do it for a nominal fee.

Q: I took my hibiscus inside about the middle of September because the temperatures at night were starting to drop. Since then, it has dropped all its flowers, buds and lots of leaves. I know they need to adjust to their new environment, but it really looks like it is dying. What should I do? (e-mail reference)

A: Give the plant a light pruning to tidy it up, keep the soil moist and the plant in as much indirect light as possible. If the plant is still alive, you should see some leaves emerging in about six weeks. If nothing happens by then, it probably is dead.

Q: I have a 26-year-old ficus tree I put outside every summer. Before bringing it in during the month of September, I spray it with a hose and use Safer’s insecticidal soap. This year, it is dripping what appears to be water from some leaves. It actually soaks the carpet in puddles. The water is not sticky, does not smell and is a clear liquid. I cannot find any webbing or other evidence of insects. (e-mail reference)

A: If it isn't sticky and there is no visible evidence of insects, the plant probably is transpiring water vapor through the stomates on the leaves and possibly the hydathodes along the leaf edges. This naturally happens all the time in a healthy plant, but I have never heard of it making puddles under the canopy.

NDSU Agriculture Communication

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