Q: I have a question regarding a poplar tree on the edge of my property. It is about 20 feet tall and about two feet in diameter and it seems like the only branches are high on the tree. It is a light color and it had a good amount of foliage this year. Does it weaken the tree if there was a recent disturbance to the ground on one side of it? Is the tree diseased if there is foliage mainly on the upper portion of the tree? (E-mail reference)

A: Soil disturbances over any part of the tree's root system will have an impact on the tree, immediately or down the road, depending on what kind of disturbance takes place. I cannot diagnose the tree's problem from what you have told me. If it is important to you, I suggest making contact with a certified arborist in your community to analyze the situation.

Q: The leaves of my lambs ears have gradually been covered with white dots that look like white measles. Over time, the whiteness spreads over the entire leaf. Any idea what this can be? Worms? Aphid eggs? I had aphids over the summer but the plant kept growing. (E-mail reference)

A: No idea what the problem is, but I would suggest dipping the plant into a solution of insecticidal soap, assuming it is in a container and if not, spraying the material directly on the foliage. This is a safe insecticide to use and is often all that is needed for control. You can also cut out and destroy the leaves that are affected the worst and lightly fertilize to encourage healthy new growth.

Q: I have two Christmas cacti which have turned brown (bark-like) right above the soil. Is this a major problem? What causes it and how do I correct it? (E-mail reference)

A: If the coloration is firm and not spongy and the rest of the plant appears healthy, then you have nothing to worry about. It’s most likely some mature tissue development. If the plant is droopy and/or discolored, then it could be a fungal canker that will eventually kill the plant. If so, I suggest taking cuttings and rooting them to perpetuate the plant.

Q: My friend and I have had our jade plants for about a year or so and they have been growing quite well. Now, for the last few weeks, they have been losing their leaves and the leaves are turning brownish/black and almost sparkly. They haven't been getting adequate light because our dorm room does not allow for it, but we try to give them artificial light whenever we can. I checked the plants for mealybugs and other insects but have not found any. One or two of the leaves turned a shade of brownish/red. Please help! (E-mail reference)

A: I am willing to bet that you are using a weak fluorescent or incandescent light instead of a Gro-Light that mimics light from the sun. If I am incorrect, then it has to do with the watering and/or drainage. If that’s the problem, then repot in a freely draining container with fresh potting soil.

Q: We take our Christmas cactus outside and place it in the shade under a spruce tree. The plant is watered only occasionally and left outside until just before frost. We then take it back into the house, water it, hang it in the light and it starts budding right away. I can't figure out how to get it to wait at least until Thanksgiving. If they don't bloom, I can get a new one for $2. I was given a Norfolk Island pine. It's over three-feet tall. Over time it lost all its branches except the top two which are showing new growth. Should I run or fight? If I cut the top off, will it re-root? Will the root grow new shoots? The original one we have is healthy and is over 6-feet tall. (E-mail reference)

A: Interesting reversal of the typical problem! I can only suggest that keeping it at lower temperatures. Keeping it at approximately 55 degrees F would slow down the bud development and opening somewhat, hopefully until Thanksgiving. The Norfolk Island pine can be air-layered. If you are interested in the process, send me your mailing address and I will send you the publication, Home Propagation Techniques, where it is described in detail along with other propagation information.

Q: What can happen to your lawn if you do not rake your leaves? (E-mail reference)

A: They will pack down under the snow over the winter and possibly encourage the development of disease organisms such as pink and grey snow mold. A light covering will not harm anything but a heavy covering will lead to problems. In the long run, grass somehow grows anyway either poorly or magnificently!

Q: I am teaching a sex education class and use question boxes. One of the questions, where are the sex organs of a green pea? (E-mail reference)

A: You have to go back to the flower for the sexual parts of the pea plant. The pod and the peas are the result of sexual fusion between pollen from the anther (male part) and the embryo sac (female part) within each flower. After fertilization takes place, the familiar pea pod begins to grow.

Q: I recently tried a delicious tea made out of the flowers of a linden tree. This made sense, after all, they do drip nectar. But I was wondering if the tree had to be a specific type of linden? If so, which type is best for making tea? I would really appreciate some help as I would like to purchase one, not only for its sweet scent and pretty form, but also to make some of that tea! (E-mail reference)

A: The flowers from the little-leaf and large-leaf linden (Tilia cordata & Tilia platyphyllos) make the best tea. If anyone in your family has heart problems, they should not consume linden flower tea. Enjoying it as an occasional tea for relaxation will do no harm but excessive consumption (5-6 cups daily) may cause heart damage over a period of time.

Q: My husband and I recently found four burr oak acorns from one of our trees. We put them into the freezer and would like to plant them. We don't know if we should take the large cap off the acorn before we plant it or which direction to place it in the ground. The tree we got them from is beautiful and healthy so hopefully the acorns will produce good trees. (E-mail reference)

A: Simply go ahead and plant them about 3-inches deep, disregarding the orientation of the acorn. If they are viable, they will sprout and grow next spring. If they aren’t viable, nothing happens.

Q: My uncle creates the most wonderful wood inlay and prizes the rare pink-colored wood you sometimes find in a Manitoba maple. He would like to know if the source of the color comes from a fungus or a viral infection of some sort and if this harms the tree in any way. (Manitoba, Canada)

A: Interesting! But, my colleagues and I have no idea what causes the pink wood that your uncle finds. There is no mention of it in the literature that we have available. Sorry I cannot be a help!

Q: I had a conversation with a lady this morning about beaver damage to her trees. I tried to explain to her the best control method is to have the problem beaver removed by trapping, but she didn't want to hear about it. She is intent on spraying her trees with paint or something paint- like to deter feeding. I didn't think this was a viable option as beaver will eat bark from ground level to 30- to 36- inches up the tree. Plus, how do you go out and spray every vulnerable tree? I think I have her talked out of that, but she still wants to spray all the trees that were damaged. Any suggestions as to type of paint, or if she should even do it? (Hettinger, N.D.)

A: Spraying trees the beaver has fed upon is of no use. The tree will heal itself, if at all, much faster without any tree wound dressing. I am afraid that her only option is to trap them. They are a protected species so she should contact a Game and Fish Department person to see what it will take to rid her property of them.

Q: What books would you recommend when looking for information on trimming, shaping and caring for trees and shrubs in this part of the United States? I would like to give it as a gift.

Also, I have tried raising hibiscus indoors by a south window. The bottom leaves always turn yellow and then fall off. I was told they like even moisture and I shouldn’t let them dry out. No matter what method of watering I try they always lose the bottom leaves. I do fertilize every few weeks with a general fertilizer like Miracle-Gro. (E-mail reference, S.D.)

A: I only know of one bookstore so you will just have to explore on your own what is there, as pruning is both an art and science that is more often learned by the school of hard knocks. A good rule of thumb with any pruning is like in cutting lumber, measure twice, cut once. Try to visualize what the tree or shrub will look like when the branch(es) is removed, and certainly have a mental image of what you want the finished product to look like after you are done pruning, otherwise you'll go too far. The hibiscus would probably benefit from a dormancy period. Allow the plant to dry and drop leaves, keeping it barely moist for about 6 - 8 weeks. Then move it to a warm, bright location with some direct sunlight daily, and begin watering heavier, allowing only the top one-half inch of soil to dry. Fertilize only during active periods of growth.

Q: I was able to get some helpful information from your Web site about the transplanting of trees. However, I still can't figure out how the root ball is formed properly if I'm dealing with sandy soil. I see where they talk about using a box, but I don't understand if the box or burlap should be placed under the root ball before lifting the tree out of the ground or later. Thanks for any help you can provide. I'm directing a boy scout that is doing this for a project. (E-mail reference)

A: I'll try my best to explain the process to you. First, determine how big a ball you can handle. Then start digging a trench around the tree at that distance, cleanly cutting the roots with your shovel or spade as you encounter them. As you dig, taper the ball so the base is smaller than the top. Once you have gone around the tree, then begin undercutting to make a clean cut of the taproot. Next take the burlap and roll it into a tube shape, sliding one end under the ball with someone helping to tip it away from you. Once you have it under as far as you can on one side, then roll the ball back the opposite way and yank the burlap through. You should have enough burlap to wrap to the top of the ball. You can secure it with cotton twine in a criss-cross fashion along with some large nails to help hold the folds in place. Then roll or lift it out of the hole to the new location.