How to Care For Your Aspen Trees

What would Colorado be without its aspen trees? While aspens are common trees found throughout North America, Colorado has a higher percentage of the species growing within its borders than any other state.

Aspen trees provide shade in summer, color in autumn, and beautiful white bark in winter. However, aspens are also susceptible to certain diseases and pests found in Colorado. Here is a short guide to aspen trees and their care.

Aspen Clones

If you have aspen trees on your property, you may notice that they send little shoots up from the ground. Each shoot becomes another aspen tree if not cut down. The shoots originated from the aspen’s roots and are considered clones of the parent plant.

You can mow the aspen shoots down where needed. However, your tree service will advise you not to use chemicals to remove the small shoots, because they remain part of the original tree. In fact, one aspen clone in Utah is 100 acres in size, 80,000 years old, and considered the largest living organism on earth.

Aspen Bark

Aspen trees are noted for their bright white bark that looks good in all seasons. That white trunk-covering is also remarkable in the tree world because it performs the role of photosynthesis for the tree.

Wildlife that ranges near aspen groves often has trouble finding food during brutal winters. Since the white bark of the aspen helps produce sugars for the tree all winter long, the bark itself becomes a nutritious food source for starving deer and elk.

Aspen Pests

Like all trees, aspens have their share of pest problems. Pests that may trouble your aspens include:

Aspen leaf miners
Sawflies
Western tent caterpillar
Poplar borer
One particularly destructive bug that infests aspens is the tiny aphid. Aphids are insects that suck sap from trees. In small numbers, aphids are relatively harmless. In heavy infestations, leaf curl and other tree damage may be noted.

Some characteristics of aphids include:

Between one-eighth and one-fourth inches long
Red, orange, or gray
Fully developed in weeks
Lay 1 to 20 eggs per day
If you see ants crawling up your aspen tree in large numbers, they may be heading for the sticky honeydew that aphids leave all over the trees they infest. Ants may begin tending aphids in order to harvest more of the honeysuckle.

Aphids and other pests can be controlled with a variety of methods from hosing down trees to having your tree service apply appropriate systemic chemicals. Insecticides and soaps are also used to remove aphids directly on leaves and branches.

Aspen Diseases

Nearly all trees are vulnerable to diseases of some sort. Fungi are responsible for most maladies that affect aspens. Spores from fungi land on trees and cause diseases including:

Leaf and shoot blight
Ink spot
Septoria leaf spot
Leaf rust
Plant diseases can affect aspen foliage in various ways. Ink spot progresses across the leaf in a continuous line of attached circles. The discoloration is light brownish in color. Leaf and shoot blight may curl outer stems of aspens and leave dark black spots on foliage.

Septoria spots on leaves may be randomly arranged, circular, and tan. Or, the spots may join to create irregular brown and black splotches across the leaf surface.

When an aspen has leaf rust, small yellowish growths cling like tiny barnacles to lower leaves. Leaf rusts are normally not a serious issue for aspens, but younger trees may be damaged or killed by heavy infections.

You can reduce and prevent aspen tree diseases with good housekeeping around your aspens. Have your tree service trim out and remove diseased branches. Wounds on trees should be dressed or treated to avoid spore and insect infestations.

Since moisture is usually necessary to spread spores and diseases, try not to get the leaves of your aspens wet. Aim sprinklers so they don’t soak leaves and branches of aspens.

Contact the tree experts at Ross Tree Service to schedule inspection, treatment, trimming, and other services for the aspen trees on your property.