News release: Protecting trees & shrubs from injury this winter, Part I

Tim Baker, MU Extension Horticulture Specialist
102 N. Main, Suite 1, Gallatin, MO 64640
660-663-3232, bakert@missouri.edu

Release Date: October 30, 2014

Headline: Protecting trees & shrubs from injury this winter, Part I

Trees and shrubs, especially young trees, may need some extra protection to prevent injury this winter. Potential damage may be from animals or environmental factors. 

Animals can kill or severely injure trees. Large animals such as deer can take care of a small tree in short order.  But small animals such as mice, voles, or rabbits can do so as well. They are especially good at eating the bark near the base of the tree. If they girdle the tree, it won’t survive.

To prevent this kind of damage on smaller trees, use a plastic tree guard. The kind that wraps around the tree and is expandable is especially good. Be sure to use a white tree guard, which will reflect light.  I’ll explain the reason in my next column. Be sure to remove tree guards in the spring.

Alternatively, or perhaps in addition to the tree guard, you may use a combination of chicken wire and ¼ inch hardware cloth to form a barrier to keep small animals from the tree.  Be sure to push this barrier into the ground several inches, since many of these animals can dig and get to your tree, if they are hungry enough.

Be sure you are not inviting small animals such as mice and voles to your tree by providing housing for them. While I’m a great fan of mulch, be sure to pull it away from the tree during the winter.  If you have a deep layer of mulch piled up against the tree, this is an ideal habitat for mice, with food (your tree) and housing (the mulch) all in the same place.

In my next column, I will discuss preventative measures for deciduous and evergreen species. But I would first like to detail several things to avoid no matter what kind of tree you are dealing with.

First, avoid late season pruning. Most pruning is best done in the late winter or early spring. Pruning done in the late summer or fall often results in quickly-growing, succulent growth.  This type of plant tissue, even though woody, is more subject to winter injury.

When you prune, be sure to form your tree to avoid narrow branch angles.  If the area where the branch is connected to the trunk is too narrow, the tree will develop bark inclusions as it grows. This is very weak, and subject to damage from ice storms and wind.

Mulch is good, in spite of my precautions above.  Mulching can help prevent freezing damage to roots in susceptible species. The key here is to keep the mulch away from the trunk, to keep the mice as far away as possible. The tree’s feeder roots are generally not right up next to the trunk anyway.

Finally, be careful with salt. Certainly snow melters are great and make walking around much safer.  But sodium chloride is rough on plants. If you would like to use such a product, choose one that is advertised as being easier on plants.