Aspens are popular for their quick growth and fluttering leaves but they are also a problem in a residential landscape. Consider the aspen to be a temporary tree. In the forest, aspens are among the first trees to grow after a forest fire. They provide a nursery for long lived trees such as evergreens and hardwoods and then they die. In a residential landscape they have a typical life of about 25 years.

Given the relatively short life span of the aspen it is good to plan for their death. Consider what you want to grow there when the aspen dies. Perhaps another aspen - there are surely some young volunteer shoots that can be encouraged or transplanted - or some new species.

Problems with aspens

Aphids can be a nuisance and a problem. Aphids occur on many types of trees and shrubs. They are small insects about 1/8 inch long and come in a variety of colors - orange, red, green. Aphids feed on the tree sap which they suck from the leaves. They also excrete a sweet and sticky material called honeydew. This attracts ants and in extreme cases can be a sticky nuisance. Aphids can be controlled by natural predators like ladybugs, or in extreme cases a systemic insecticide can be placed into the tree.

Aspen are also a frequent target of the oystershell scale insect. This is a most unusual creature. It spends a short time each year in a crawler phase when it can move about. Then for the rest of the year it attaches to the bark, builds a white waxy covering to protect it and sucks juices from the tree. This covering looks a bit like a very small oyster shell - thus the name. In small numbers this is not very damaging but the numbers can quickly become large and a heavy infestation can kill branches or cause the tree to decline and die. Control of scales is difficult because of the waxy coating that protects the insect. Systemic insecticides in the tree controls this pest.

Cytospora canker is a disease caused by fungus of the Cytospora family. The fungus attacks trees or branches that are weak or stressed by drought, insects or mechanical damage. Symptoms include discolored areas of the bark - generally orange to black. This is often accompanied by a liquid goosing from the bark.

The first consideration for controlling this problem is the conditions that lead to weakness in the trees. Either drought or a constant flood or water in the soil are common stresses. Oystershell scale or other insects can stress the trees. Good nutrition with trace minerals are also important in residential landscapes.

The first step to treatment is to increase plant vigor - proper watering and fertilization. Then remove all infected limbs.

Remove Dead trees. Dead trees can harbor fungus that become active when wetted by rain. Fungus propagates by broadcasting spores into the air for transmission to other trees. If a tree is dead or too far declined in health to save, it is best to remove and dispose of the tree.

My experience here is that fertilization with BioMax encourages healthy aspens. One treatment is usually sufficient for several years.




TreeHealers
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Larry Sanders