Q: I have a Norway maple with longitudinal cracks from the ground up. I know this is normal for this species, but my question concerns structural integrity.
Two tree service companies have looked at it and given me removal estimates.
However, there was no clear opinion on whether the integrity of the tree is compromised enough to warrant removing it. The tree is at least 50 years old.
What are your thoughts? (e-mail reference)
A: Obviously, the two tree service companies like to take trees down rather than attempt to save them. I would try a company that has an International Society of Arboriculture certified arborist. To get a listing for your area, go to www.treesaregood .
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org/findtreeservices/FindTreeCareService.aspx. If the vertical cracks go into the heartwood of the tree, there is a chance the tree is rotting. If that is true, removing the tree would be highly recommended. If the cracks are just in the bark and have healed, then the tree probably is sound.
Increment borings taken by the arborist can determine if the interior of the tree has started rotting. Standing and looking at the tree without such a test is not a valid determination because too much of the tree is hidden.
Q: We recently purchased a home that has a row of junipers mixed in with long-needle spruce trees. As a result, the junipers and the spruce are stunted. We would like to move the junipers but are not sure if the roots are too intertwined to move. Do you have any suggestions on how to move them so that all of the trees survive? (e-mail reference)
A: Trees with intermingled roots that have been in the ground for a long period of time do not transplant well at all. The grafting of roots occurs within species, so a lot of root damage is bound to occur during any transplanting.
This also is something that beginners should not attempt to do. You would be better off hiring a landscape contractor or someone who has a small landscape business to do the transplanting or removing the trees. The stunting could come from deciduous trees or surrounding structures casting too much shade because spruce and juniper trees are planted adjacent to each other a lot.
Q: What does "when the fruit has set" mean? (e-mail reference)
A: It simply means that the fertilization of the flower was completed, so the fruit is now developing from an embryonic size to harvestable size. In common parlance, growers often will view a tree, vine, shrub or plant and say there is a good fruit set upon seeing the large number of developing fruits.
Q: I've had a mammillaria pilcayensis for about seven months. For a while, it was growing well. Every few days or so, I would rotate it because it would start to lean toward the sun. However, for the past couple of weeks, I haven't needed to rotate it because it's staying leaned away from the window. I'm wondering if there's something I can do to help it grow straight again. Having read most of the other e-mails you have answered, I realized that I've probably been overwatering it. Could that cause it to stay leaning?
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The store where I bought the plant had glued a dried flower on it. After a few months, I carefully removed it because it looked silly once the cactus started growing, and I figured it wasn't doing anything for the plant. When I pulled it off, about four groups of spines came off with it and haven't grown back. I read that the spines are important for protecting the cactus from the sun. Could this little bald spot be hurting my cactus? (e-mail reference)
A: I don't think that would be the cause of your problem. If it is, the problem should correct itself. I would try a plant light directed at the cactus. It could be that the light coming in through your window is too weak to have a tropical effect. I'm assuming you live up north with us where the moonlight is now almost brighter than the sunlight we get.
Q: I planted a Bradford pear tree in my yard in 2001. It's currently about 18 feet tall and 10 feet wide at the base. However, I have a couple of concerns.
It's dormant for a very short period of time each year. Last year, it was early February before the leaves dropped, and then it began budding again in late March. Last winter and early spring were cold and snowy. In the fall, the tree displays very little color. It starts to turn color on just a few scattered leaves, but then the color change stops and it remains green until midwinter, when the leaves eventually turn brown and fall off. In the spring when the tree buds, there are very few of the white blossoms that are a characteristic of this type of tree. The few white blossoms that it gets are scattered and buried among the leaves. (Detroit)
A: The tree obviously had a good history of growth prior to last year. The large canopy spread you described is a good sign of tree vigor. What probably is happening is that the tree is not adapting well to wet, cool fall and early winter conditions. Color comes from the genetic potential of the tree and the weather conditions. Bright, sunny weather and cool, clear nights are what get the tree to change color to its full potential. If it never has done this, then this is an indication the tree is at the edge of its hardiness range, which is zone five. You might have a microclimate that borders between hardiness zones four and five. These trees are better adapted to the South for fall coloration and blooming ability. Typically, when they are planted in the North, the leaves will hold late. The timing of the first cold snaps could have a direct effect on the fall coloration. Essentially, there is nothing wrong with your tree. However, it just isn't as happy as it would be if planted somewhere farther south.
Q: I have a purple plum tree, but I don't know what variety it is. Two years ago, the plums became infected with an apparent fungus. The plums got small fruiting bodies all over as they matured. About 75 percent of the plums were infected. Many dried up and hung on the tree. Some hung on the tree for two years. Can you determine the cause and give me a cure for the problem? (e-mail reference)
A: This could be a direct fungal disease that is hitting the plums or a secondary rot that is the result of the feeding activity of plum curculio larvae. In both cases, remove any mummified plums remaining on the tree and those that have fallen to the ground. A protective dormant spray of lime sulfur and dormant oil will take care of any spores remaining in the bark crevices, as well as any overwintering insect eggs. When the blossoms begin dropping, spray the tree with an orchard spray that is a combination of fungicide and insecticide that will cover the embryonic fruit. Repeat again about 10 days after fruit drop.
Q: I've had a Madagascar palm for 20-plus years. It is about 7 feet tall and kept indoors because I live in Canada. Recently, the tree has had trouble keeping its leaves. The leaves tend to turn black and fall off. It is in a 20-inch diameter pot and has started to fall over. I just noticed that the top of the tree is brown and the trunk can be indented by pushing on it. It looks like it is dying. The tree does have one branch that is green. Is it possible to save it? Can I take a cutting from it? (Alberta, Canada)
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A: This borders on the amazing if not the impossible! Someone in Alberta growing a Madagascar palm indoors to a height of 7 feet and having kept it alive for more than 20 years. Obviously, you have been doing what is right for the plant until recently. Did you move it or change watering habits? About all I can tell you is that it doesn't sound like your plant is long for this world. These palm trees require as much sunlight as possible and high temperatures (80-plus degrees). It needs limited watering during dormant periods and light, frequent watering and fertilization during periods of active growth. If there is a green offshoot, carefully remove it and allow it to cure for three to four days before planting it in a pot and then hope it will take root. You must have a very strong light source to augment the low light levels you would experience during Alberta winters.
Q: I've had my ficus tree for more than 35 years, so it is very dear to me.
About six months ago, I noticed a black, powdery substance on top of the leaves.
If I leave it, the substance gets heavier and heavier until the leaf dies and falls off. I have washed each leaf, but the substance keeps coming back. I would hate to lose this tree after so many years. What can I do? It is not scale because the leaves are dry and there is nothing on the bottom of the leaves. (e-mail reference)
A: The black substance doesn't register with me. Generally, a film covering the foliage is due to powdery mildew. However, powdery mildew usually is white, not black. I suggest that you try to obtain some fungicidal soap that should be available at local nursery or garden center outlets. Use the soap to wipe the leaves off and then spray the plant with the same material once you have cleaned the foliage.
To contact Ron Smith for answers to your questions, write to Ron Smith, NDSU Department of Plant Sciences, Department 7670, Box 6050, Fargo, ND 58108-6050 or e-mail ronald.smith@ndsu.edu .
