Garden Tips for September
We thank the ALCC for this great article on tree maintenance.
Trees: They are often quite stately standing next to our homes and offices. They shade our homes and our picnics. But they usually don’t grab our attention like the lawn does every Saturday morning because unlike the lawn, they don’t clamor for weekly maintenance. It’s easy to take them for granted and think they pretty much take care of themselves. Think again.
Trees are often one of the biggest costs when we first landscape our homes. And unlike most home improvements, they don’t decrease in value–they actually increase in value over time if kept healthy. As property owners, we need to know that trees can require different care from year to year.
What’s different about tree care this year? We had record dry winter followed by a record wet spring and each one of these conditions had its own impact on trees. Because of the dry winter, there are a lot of dead branches. The wet spring–particularly the rains in May–brought fast growth and more growth than we usually see.
We need to prune out the dead wood from the winter and also, get excessive new growth out before it snows again. Heavy snowfall can be very damaging to trees and the way to avoid it is with proper pruning, this year in particular.
Insects : In 2011 we have two tree problems that aren’t major ones and two that are more serious. This is a banner year for aphids and we know it from their tell-tale honeydew–that drippy residue. Aphids are really more of a nuisance than a serious threat to the trees’ health.
The other non-serious problem this year is oak blister. Property owners need to be aware of it more so they know it’s something they DON’T need to worry about because the symptoms are unsightly. This disease is only on the leaves of oak trees. It causes leaves to fall off the tree and 10-20% of the leaves will turn brown. All of this makes people worry about their oaks, but it looks more serious than it is.
What are the serious tree problems? European elm scale. This problem relates to elm trees and we have many of them along the Front Range. This scale affects only the twigs and branches of the tree. The scales suck out the sap and that causes the branches to die. Scales are treatable and this is one problem you should monitor and treat, as needed, for the health of the tree.
Mountain Pine Beetle.: This is the same problem we’ve faced in the mountains for several years that has destroyed so much of the pine forest. It first hit Denver last fall. Most arborists are worried about the threat to Scotch pine and ponderosa pine, in particular. This problem can only be treated as a preventive measure. Once the tree is attacked, it’s too late.
Arborists and others who have been watching pine beetle think the beetle will start attacking trees along the Front Range in August/September. If you have trees at risk that you want to protect, it’s best to schedule treatment before the outbreak.