Q. I had terrible leaf blight on my aspens this year. Is there anything I can do this fall to prevent this from happening? - Missoula County
A. Here are some quick facts about foliage disease, often called leaf spot, of aspen and poplars:
This fall, rake and dispose of leaves around the tree to reduce the bacteria or fungus that overwinters in the leaf matter. Be sure that the aspen and poplar leaves are burned or taken to the landfill. Do not put them in the compost pile.
In general, focus on supporting tree health by providing adequate water and nutrients during the growing season. Next year, make sure to water in the early morning, don’t let the sprinkler spray the leaves of the tree, and be sure to prune or space trees for good air movement between trees and branches. It has been noted that trees that are iron deficient are more susceptible to certain leaf spots. If you live in an area with a high soil pH, which includes most of Montana, it may be helpful to add iron or elemental sulfur (which makes iron in the soil available to the tree) to the soil to help the tree be less prone to the disease.
If you decide to spray a fungicide, remember that the fungicides for leaf blights are preventative and will only work if sprayed before the tree is showing symptoms. Contact your local MSU Extension agent or another plant professional for advice on whether fungicide treatments or additives to the soil are needed.
Q. When should I put my tree trunk protectors around my trees? - Powell County
A. Tree protectors are used to prevent sun scald, which usually doesn’t occur until late winter. However, it is recommended to put them on in the fall to help keep the trunk protected from deer, elk or moose damage. They can also help protect the trunk from vole damage. Putting them on in the fall will also prevent you from tromping around in the snow and cold to install them later in the winter. When installing trunk protectors, be sure to protect the trees (especially smooth or dark-bark trees) up to the first branch. If a deer or elk rubs on the trunk, even the best tree trunk protector for sunscald may not be enough to keep the tree safe. If this is the case, also consider fencing off the tree.
Do you have Master Gardener questions? Send them to: extensionmagazine@montana.edu.