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

By Ron Smith, Horticulturist

NDSU Extension Service

Q: I was looking at the Web page with all of the questions you’ve answered through the years. I looked at the iris plant page and your reply about labeling iris plants during blooming for replanting later. I wanted to tell you about my experience. Years ago, I labeled the leaves during blooming with a UV-proof garden marker. It was a good idea, but by fall, the iris plants had shed all of those leaves that were green during blooming. They had been replaced by new leaves. I wouldn’t have guessed that this happens, but I pull brown, curled leaves away every fall. The only way I have found to label the plants since then has been to write the color on the bloom stalk, which might shrivel, but stay. A better way is to write the color right onto the brown rhizome where it is above ground. However, you need to use a UV-proof garden marker. This past year, I pushed a little labeled stake (cut from a sour cream container) into the ground by each clump (won’t fade). As I dug them up, I found the stake and then I wrote the color name onto each division so that the people I gave them to would know the color. I liked this method. (Carrington, N.D.)

A: Thanks for the nice note! Of course, you are right. I simply got it wrong! It would work OK if it was necessary to dig the iris up immediately after flowering. By fall, as you say, there is nothing there to identify the color unless you happen to have a photographic memory. Your method of adding an indelible tag or stake to or near the crown is the best idea to not lose the color scheme.

Q: I have three aspens growing close to my home that need to be removed because they are providing our local squirrels and raccoons a highway to our roof. Should the stumps also be removed (ground out) or should stump remover be used? I'm concerned about suckers. These trees will leaf out in April, but they need to be cut down within the next week because we are having our roof replaced. (Denver, Colo.)

A: Get the stumps ground out. I had similar problems with my aspens. If you don't get rid of the stumps and most of the support roots, you will have suckers coming up all over the place. You'll still get some, but not as many.

Q: We planted five hot wings maple trees (Acer tataricum 'GarAnn’) along the boulevard in our front yard in 2005. I pulled small seedlings with roots about 5 to 6 inches long from the mulch in the flower beds. I planted three seedlings in the ground and three in pots. Will these small seedlings grow to be the same as the parent trees? Our neighbor across the street has admired the trees and also would like to plant some. We live in a small town with no restrictions as to the type of tree we can grow. (Washburn, N.D.)

A: The hot wing maple is a clonal cultivar that only can be propagated asexually. Everyone who sees this beauty wants one. It has everything going for it, such as alkaline soil tolerance, beautiful fall color, brilliant samaras (fruit) and few, if any, pest problems. Enjoy your tree, but tell your neighbor he or she will have to "belly up to the nursery" and purchase his or her own!

Q: I purchased two large goldfish plant hanging baskets last spring. I brought the plants inside to protect them from the freezing temperatures. However, one plant has lost all of its leaves but seems to have healthy stems. Is it in its sleeping mode? Should I cut the plants back? If so, how much? (Birmingham, Ala.)

A: The plant likely got nailed by a cold draft of air or it is in a very dry air location. You can give it a light pruning if you wish, but that usually is done after the plant has finished flowering. It may be getting too little light indoors. You might want to consider setting up a plant light on a timer to give it a 12-plus-hour daily dose of light energy. Another suggestion is to purchase a room humidifier for these plants. Keep in mind that their native habitat is under trees in the shade of tropical rain forests. The closer you can come to aping that environment, the better the plants will respond.

Q: I have a line of Scotch pines that are 30-plus years old. They seem healthy, but three-fourths of the trunks are barren. I assume it's owing to the blockage of light caused by a maple tree. If the maple was removed, is there a chance that the pine trunks would fill in rather than remain barren? (e-mail reference)

A: Not very likely. This is a characteristic of Scotch and Ponderosa pines. They develop “character” as they age whether or not they are in an open or semishady location. Would the pines grow better under full sun? Without a doubt, but it wouldn't change the character you describe. That must be some maple to be blocking light along a line of pines that old!

Q: I have been reading up a lot on night crawlers. I've come across a few Web sites that say night crawlers can’t survive above 65 degrees. However, I remember catching them during the summer in Connecticut where it gets well above 65 degrees in the summer. (e-mail reference)

A: Survival of these soil invaders depends mostly on the moisture level in the soil. Dry soil will kill them at a lower temperature. Moist, but not saturated, soil will keep them alive into the upper 70s and low 80s. Exposure to radiant sunshine kills them quicker than anything else. That’s way you have the conspicuous presence of fried earthworms on sidewalks following a flooding rain. They cannot survive in flooded soil, so they migrate to the surface for air. If they don't get back into the soil quickly enough, the sun will kill them.

Q: I live in New York City with a potted birch tree on my deck. It is in a relatively protected area. The deck is on the second floor and surrounded by buildings. It is potted in a wooden box about 4 feet deep and 3 feet wide. The tree has lived happily there since 2001. However, the box is breaking. I'm thinking of a larger planter, but I'm concerned about the weight. I'm also concerned about when and how much I should water it during the winter. For example, we are going through a long stretch right now where it gets up to the lower and mid-40s during the day but below freezing at night. We have not had much rain or snow this winter. (e-mail reference)

A: I wouldn't recommend going larger with the container because the plant is on a deck, so the increased weight could be an issue. I would get a competent carpenter to come out and either shore up the present box or build another one of stouter wood. Since the tree is in the winter dormant stage, there is little need for water during this time. However, the soil should not be allowed to dry completely. Keep it moist enough so that when an extended cold spell comes on, the outer edges of the rootball are frozen. By the way, congratulations on keeping this tree alive for so long under these conditions.

Q: I have a very old sugar maple. Do you know how to determine its age? From the formula I found, the tree is 225 years old. The house I live in was built in 1869. I do have a picture from 1902 that shows a pretty big tree. Any rough idea on how tall a tree would be at different ages? (e-mail reference)

A: The accurate determination of a tree’s age is difficult to arrive at. When young, all trees grow with youthful vigor. As they age, the increase in height, as well as circumference, slows. Since the house is 141 years old, the trees would have been more than 80 years old at the time of construction. It would make sense back in those days of no air conditioning to build a structure that would benefit from the shade of large trees. If you want to nail the age a little closer, contact an International Society of Arboretum certified arborist in your region who can take a small boring out of the tree to nail its age to within a few years. Usually, the state forester would be interested in trees this age. Foresters are constantly on the lookout for senior citizen trees of a particular species. The listed national champion sugar maple is in Kingston, N.H. The tree is 87 feet tall and has a crown spread of 100 feet. Assuming you live somewhere in New England, your tree may challenge the record!

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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