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

By Ron Smith, Horticulturist

NDSU Extension Service

Q: While my husband was burning weeds in the yard, the wind shifted and caught one of our blue spruce trees on fire. He got the fire put out, but not before it burned about one-fourth of the needles and branches on one side. Will the tree come back? (e-mail reference)

A: Difficult to say if the tree will recover. The part of the plant that caught fire probably had all the meristematic tissue killed. In that case, that part of the tree will not recover. As for the rest of the tree, it depends on how hot the fire got before it was put out. If the tree is disfigured, it probably should be removed. It will never regain the majestic form that everyone loves. Sorry!

Q: In your forum, someone asked about their grandmother's three Christmas cactus plants changing to white blooms. I have the same problem. My cactus is full of beautiful blooms and is very healthy. I keep it near a west window in the garage during the winter. The garage is cool but not freezing. During the summer months, I put the plant on my screened porch. The porch faces south, so the plant gets good light and some direct sun all summer. I water it sparingly and fertilize it once or twice a year using a liquid fertilizer. I brought it inside about the end of November when I heard it may get below freezing outside. I did repot it this past year. However, I don't remember what I used as a potting soil. This is the third year I've had it, but the first year it has bloomed. It will go out in the garage once the blooms are finished. I'm thinking about experimenting with the plant but I’m not sure what I will do. I might change the pH levels or use a different type of potting soil. If you have any ideas, let me know. It is pretty right now, but I’d rather have the bolder fuchsia/pink blooms. (e-mail reference)

A: I definitely would be interested in any experiments you may conduct on your Christmas cactus! It is a very alluring plant when in flower. Keep me posted!

Q: The narrow-leafed cottonwood trees in our area have bushy trunks from the ground up. We commonly refer to it as a “beard.” Has an ecological purpose or survival strategy for this growth form ever been determined or theorized upon? Is there any harm or disadvantage to the tree if the beard is trimmed? (e-mail reference)

A: Cottonwood trees are notorious for this sucker growth. It usually comes as a result of the upper part of the tree undergoing some kind of stress, so the beard is a survival mechanism for the species. Removing the bushy growth should not pose any kind of hazard to the tree. When I was running a nursery and landscape contracting company in Saudi Arabia, we had a tree farm where we had some cottonwoods planted that were flood irrigated. This is an extremely inefficient way of distributing water uniformly over the root system. I had the nursery staff dig some of the trees up and put them in containers. The containers then were put under a drip irrigation system. In operating such a system, the water would percolate through the containers and soak into the sandy soil below. The water nourished the roots of the remaining trees. Shortly after that, we had a forest of sucker growth from the roots in the ground. We selected the best ones and dug out the worst. The result was an increase in our inventory, so we didn’t have to buy any more trees. This drove the accountant for the company almost crazy because he was good at accounting but didn’t understand plant growth until I convinced him this is what happens with cottonwoods.

Q: I have a large spider plant that I bring inside right before the first freeze. It is growing quite large, so I’m wondering if I can plant it in the ground. Would it survive Virginia winters? If it is possible, how could I help it survive? (Richmond, Va.)

A: You have freezing temperatures during the winter in Richmond, so that eliminates the possibility of planting it outdoors. Why not divide the plant in half or quarters and give some of it away to family and friends? These plants become part of the family after a few years, so you don’t want to kill it by placing a tropical plant outdoors where it will freeze to death. I don’t think you could mulch it enough to keep it alive. If you divide it into quarters, keep one indoors, give two quarters away and plant the other quarter outside as an experiment. Be sure to give the plant outside all the protection possible.

Q: My stupid cat knocked down my croton plant and broke off the whole root system. Can I put a root hormone on the end of it and stick it in water? I have it stuck in the dirt right now. (e-mail reference)

A: Do a fresh cut across the base of the root (at a slant if possible). After that, dip it in hormone rooting powder and stick it in damp sand with a clear plastic bag loosely covering it. If it has started to wilt, it may be too late for it to recover.

Q: We planted blue spruce trees last spring. They did well this summer. Now that we have a lot of snow, the trees are completely covered. We're unsure if this is a good or bad thing to have happen. Could the trees be damaged by the snow cover? (e-mail reference)

A: I would suggest leaving them alone. The snow blankets them in a natural setting, so they will be OK.

Q: I gave a friend of mine a ficus as a housewarming present. I just found out that she found worms in the drip tray under the plant and it is dropping leaves. The branches on the inside are brittle. She thought the worms were gross, so she put the plant in her garage! We live in Canada and the temperature here is minus 13 Celsius. After I found out, I immediately rescued the plant. How can I save it? I put it in my bathroom and have the shower running to steam up the room. Please help. (e-mail reference)

A: If you believe in giving a houseplant its last rites, I’d suggest that you do so because there is no hope for this plant to recover from exposure to a temperature that low. At that temperature, the cambium and bud tissue are killed outright on plants native to the tropics. What your friend was likely seeing were some larval-stage insects that were washed out of the soil during the watering process. Retailers of houseplants in North America are inundated with plants dug up in southern states, such as Florida, California and Texas. The growers have the plants growing in the ground until they get to retail size. After that, the growers put the plants in pots using local soil that has not been pasteurized, so the insects remain alive. I wish there was something I could tell you that would get this plant to recover from the freezing ordeal. Sorry!

Q: We planted a live, 10-year-old oak tree. We were watering the tree at least once a day or every other day. One day, we looked out the window and saw that all the leaves were turning brown. The tree doesn’t appear to have any bugs. It was planted by the nursery, so it was planted at the right depth. Most of the branches snap off. There is a green sprig coming out of the ground at the base of the tree. Can you think of anything that might help the tree? We have put root stimulant on it. Can you overwater a live oak tree? I hate to lose this beautiful tree. Please help. (e-mail reference)

A: Generally, the older and larger a tree is when planted, the greater the risk of losing it. I hope the nursery that planted it for you provided explicit instructions on care and watering. I also hope the nursery sold it with a guarantee. A number of things can kill a live oak tree, such as low temperatures, anaerobic conditions in the soil from overwatering, planting it even a little too deeply and excess root loss during the digging and planting process. If this was a containerized tree, which isn’t likely because of its size, it probably was growing in the ground and dug up by hand or pulled out using a tree spade. The fact that you are witnessing new growth coming from the crown could be an indication of low-temperature damage to the aerial part of the tree. There also could be bark beetles that could have girdled the tree and killed it from the point of girdling on up. You need to get nursery staff to examine the tree to see if you can get it replaced for free or at a reduced price. If you go this route, I’d suggest going for a smaller tree. It will have a greater volume of roots to sustain it, have the vigor of youth and be much lower in price.

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 – Dec. 22, 2010

Source:Ron Smith, (701) 231-7123,
Editor:Rich Mattern, (701) 231-6136,
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