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

By Ron Smith, Horticulturist

NDSU Extension Service

Q: Is there a certain tree you would recommend that has a better lifespan than others when choosing a Christmas tree? (e-mail reference)

A.Generally, pines with long needles, such as white and scotch, have the ability to hold needles longer than those with shorter needles, such as firs, and certainly longer than any spruce tree. With every bit of good information must come a little negative news. It is more difficult to vacuum around Christmas trees with longer needles. It also has been my experience that trees with longer needles take a little more time and effort to decorate.

Q: What's the best way to keep a Christmas tree alive when purchasing it early in the season? (e-mail reference)

A.Make a fresh cut about 2 inches off the bottom stump. This will unclog the water-conducting cylinders in the trunk and allow water to be carried to the branches and needles. The first time water is added to the stand, it likely will all be taken up in about 30 minutes. Be sure to monitor this and refill immediately. Some people have their own techniques for extending the life of their trees that they swear by. Some people add unbuffered aspirin, 7-Up, Coke, Sprite or something else. Go with what you believe in, but research shows that plain water maintained consistently above the stump base will keep trees fresh for up to five weeks.

Q: What should I do to keep a poinsettia plant alive so it will bloom again next year? (e-mail reference)

A.Usually, the best procedure is to dump the poinsettia after the beauty is gone. However many folks want to attempt to keep it going for next season. In that case, keep the plant in a well-lit location. Water the plant just enough to keep it alive. It will become ratty looking eventually, but if you can keep it alive until planting time next spring, the plant will rebound beautifully if you set it outdoors in a protected location. Cuttings can be taken as it produces lush, new growth. These cuttings will root easily so the new poinsettia plants can become the show-off plants for the 2010 Christmas season!

Q: I have a problem with scale. I have used a detergent and water mix and made sure every little bit got on the bulbs. However, I still have the problem. What can I do to get rid of these pests? (e-mail reference)

A:Scale insects are difficult to control. It takes a concerted effort on your part to bring their number down to a level that will not be harmful to the plant. If your attempt with the detergent and water did not work, then likely you are dealing with what are known as armored scale. Try getting a hold of a facial sponge that is not treated with a cosmetic product. Use the sponge, along with rubbing alcohol, to try to wipe the pests out. Normal pressure (not hard pressing) such as you would use on yourself should break the barrier and kill the scale. Keep in mind that the alcohol will kill these pests, but their bodies will remain. Getting the armor coverings off likely would do more damage to the plant. Judge your success or failure by whether or not the scale population seems to be stabilized or increasing. If it is increasing, then dump the plant and get another one for the holidays. Try a small section of the plant with this alcohol rub to be sure there is not going to be a negative reaction.

Q: I neglected to ask about the red splotches and streaks on the leaves of many of my older amaryllis plants. I just invested in new bulbs and don't want them to become contaminated. How can I treat this redness in the greenery? (e-mail reference)

A: I think this may be a virus that is embedded in the amaryllis plants. If that is the case, there is no treatment for it. However, while being a distraction, the problem may not be lethal to the plants. To be sure of what the problem may be, a lab culture needs to be taken.

Q: I have a Miss Kim lilac bush by that has grown too tall. When is the proper time to prune it back? How low can I cut it back? (e-mail reference)

A: Anytime next spring before new growth begins is when it should be pruned. You can prune it back to just above the crown. These lilacs are not supposed to grow too tall. I think you are the first person to complain about this beautiful plant getting too tall.

Q: Last year I wrote to you for advice on transplanting three large spruce trees. Your advice was terrific and the transplanting went well. The trees were doing fine during the summer. However, I’ve noticed that they are starting to show some browning in the middle. We had lots of rain during the summer. Do spruce trees go dormant? Could that be what I'm noticing? Any help would be appreciated because my wife and I love the trees and would be devastated if they were dying. (Boston, Mass.)

A: This is probably just the normal aging of the older foliage. It occurs annually with evergreens. What happens is that the oldest interior foliage will die and drop off. As long as the current or previous season's growth is not affected, they should be all right. Enjoy these beautiful trees.

Q: I purchased a jasmine plant this past summer from a local greenhouse. It was in full bloom when I got it, but hasn't bloomed since. What can I do to get it to bloom? I brought it indoors for the winter, but could it survive outside in our area? It was heavily infested with mealy bugs, but I have most of that under control now. Any advice would be much appreciated. (Fargo, N.D.)

A: Good idea bringing the jasmine plant indoors for the winter. It would not survive being outdoors during Fargo's winter months. Reblooming likely will take place later in the spring if it gets enough natural and supplemental light from a plant lighting system. Mealy bug infestations are difficult to control. It requires the careful use of insecticides, as well as judicious pruning. Monitor the plant carefully. Should the mealy bugs become noticeable again, prepare a solution of insecticidal soap to dip the entire aerial part of the plant into. This will effectively eliminate missing any bugs.

Q: How deep do weeping willow roots grow? (e-mail reference)

A: This is not a question I can answer with any degree of accuracy. It depends mostly on the type of soil you have and the water situation. The water situation would include the annual rainfall pattern, amount of rainfall and your watering practices. For the most part, weeping willows spread out more than they go deep. As with most root systems, weeping willows will develop in a soil environment where there is a balance of air and water, although the willow is more tolerant of saturated soils than most tree species. This species of trees will go where the water is and follow the path of least resistance. If there is a water source under the ground that the roots have picked up in their exploration of the soil and it happens to be a sewer line break or septic leakage, the roots will proliferate in that nutrient-rich area. Count on the roots spreading 35 to 50 feet from the tree's trunk. The depth of the roots depends a lot on variable factors. This species often is used along stream banks to prevent erosion because of its formidable root system.

Q: I am looking for help with an African violet problem. The plant is healthy, but the violets are becoming overgrown, overcrowded and hard to the touch in the crown. The new leaves and blooms can’t force their way out of that tough, hard-leaf overgrowth. What’s wrong? (e-mail reference)

A: The poor thing needs dividing! African violets, despite the popular myth that they are delicate houseplants that need fussing over, are almost weedlike in their native environment. To divide the plant, allow the soil to dry slightly, then tap the plant from the container and place it on a workbench or open newspaper. Separate as much of the soil from the root mass as possible, then cut through the crown with a knife, scissor or small pruner. Take the divisions and plant them in a premoistened soil mixture. Keep the soil moist for a few days. Then allow the soil to remain slightly dry for the next couple of weeks so the plant can recover from the shock of division and transplanting. If you have a multicrown plant, divide the multiple crowns by hand and repot.

Q: I mistakenly cut the center leaf of my spider plant. It looks like I snipped off the new growth. Does the plant grow from the center and will it recover? (e-mail reference)

A: If it was healthy, it will recover and grow new foliage.

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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