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?
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.
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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, Dept. 7670, Box 6050, Fargo, ND 58108-6050 or e-mail ronald.smith@ndsu.edu .
