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

By Ron Smith, Horticulturist

NDSU Extension Service

Q: I bought an amaryllis plant and am wondering how tall it will get. So far, the plant is growing about an inch or two per day. When will it stop? It’s outgrowing all my other plants. (e-mail response)

A: This is quite normal. Growth depends on the hybrid you have and the size of the bulb it is growing from. Larger bulbs equal bigger, taller plants with more flowers. When it does stop growing, it should give you a feast of beautiful flowers to enjoy!

Q: I planted a little pine tree in my backyard during 2008. It has survived and is about 2 1/2 feet tall. However, we just had 17 inches of snow that knocked off all the needles and little branches. All that's left is what looks like a stick in the ground with a small tuft of needles and twigs at the top. What will happen to this tree this summer? Is it going to die? If not, is there anything I should do for this tree right now or next summer? (e-mail reference)

A: It sounds like you have the perfect Charlie Brown Christmas tree! Keep in mind that seedlings are exposed to this kind of abuse all the time, but the majority of them survive somehow. Is your particular tree fit enough to survive? Time will tell. I know you have genuine concerns, so let me suggest some solutions. Build a little tepee over the top of the tree to protect it from other Mother Nature problems, such as bunnies nibbling on the last wisp of greenery. You can use garden or snow fencing to surround the plant and then place something sturdy and waterproof over the top. If you still can find it on the market, you could put a Styrofoam rose cone over the plant until the snow melts next spring. Another possibility is to drive three oak stakes into the ground and then put a sheet of burlap around and over the top of the tree. Do whatever you can at this point to protect the tree from any further damage. Since the tree has been planted for more than a year, it has a good amount of energy stored in the remaining tissue, so it may grow robustly for you this next season.

Q: My poinsettia was attacked by whiteflies. How do I get rid of them so the plant will live? (e-mail reference)

A: There are a lot of insecticides that will control whiteflies. However, the best way to do this with a houseplant is to get some insecticidal soap. Make a solution in a large enough container so you can dip the entire plant in it for a few seconds. This solution kills the pests on contact. Be sure to follow label directions.

Q: I want to make my own potting mix to grow landscape plants, trees and shrubs from seeds. Can you recommend some ingredients and the right amounts for me to create my own mix? I grow everything from seeds, bulbs or acorns. (e-mail reference)

A: Landscape plants can be grown in any number of combinations using sand, clay and organic matter. There is the Cornell Mix, UC Mix (University of California) and probably a dozen or more that are lesser known. If you talk to nursery operators, they have their own favorite secret formulations. Following typical recommendations, I would advise you to try to use as many natural local ingredients as possible to keep your expenses to a minimum. You need to define what it is you want to grow and then do some research on what the basic soil requirements would be for the plants, such as acid pH, alkaline pH or pH indifferent. Also, you need excellent drainage. I would suggest experimenting on a small scale to create your own designer soil. You can use three parts sharp sand, three parts compost or some other well-weathered organic matter and two parts topsoil. If you are going to be starting plants using cuttings, I strongly suggest soil pasteurization (180 degrees for 20 to 30 minutes) to remove one of the potential barriers to success. Go to or,7518,s1-5-21-185,00.html for more information. A precautionary word or two because some of these mixes call for the use of perlite and/or vermiculite: While both have excellent drainage characteristics, it has been found that perlite tends to separate out and migrate to the top. Vermiculite from some sources contains trace amounts of asbestos, so use either with this in mind.

Q: How can I vernalize an amaryllis plant so it will flower? The last two times I let a bulb that had flowered grow for quite some time to build up its root reserves. I then cut it off and placed it in a dry place in the basement for several months. The temperature is about 65 degrees in the basement. When I replant the bulbs, all I get is green foliage, but no flowers. What am I doing wrong? (Fargo, N.D.)

A: This will be a burning question for many people after the New Year arrives and the flowers begin fading. The foliage never should be cut off while it is still green. After summering it outdoors, bring it inside in mid to late September. Store it in a dark, cool location and withhold all watering. Note the words cool and dark. The temperature never should reach freezing. This will cause the foliage to yellow and turn brown. After it does, remove the foliage, but never cut off any green leaves. This should be done for an eight- to 10-week period. This time frame should be enough of a rest period for the bulb to reset new flower buds. After that, bring it back into strong interior light (south window if possible) or provide light energy from a Gro-Lux bulb set on 12-hour cycles. Give the plant bulb a good shot of tepid water and then wait. If the bulb is ready to bloom, it will produce a flowering stalk that should grow quickly. Try this dry-down cycle of getting the foliage to lose chlorophyll content and I think you will have better luck getting the bulb to rebloom because this method approximates what takes place in nature.

Q: I am having a huge American elm tree cut down. I think the tree is healthy. The only problem it has is some English ivy growing all over it. I need to cut it out because it is enormous and is causing cracks in my house and driveway. Is there a way I can cut a branch from the tree and have it grow roots? I am getting into bonsai and I have a hill behind the house. I would like to keep some part of this tree going either on my back hill or as a bonsai because the tree obviously is a survivor. Can you help me do that? (West Virginia)

A: Cuttings can be rooted, but with difficulty at this time of year. What typically happens when a tree this mature is cut down is that the roots send up sucker growth. These suckers are much easier to root. This would take place in the spring, so you could remove some of the suckers, dip them in a rooting hormone and attempt to get them rooted. You also can download my "Home Propagation Techniques" publication for more hints. To find it, go to

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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