Garden Talk- Should we worry about our trees?

Unusually mild temperatures through much of February sparked worries among gardeners. While we know that spring-flowering bulbs such as snowdrops and crocuses are very hardy, what about our trees that are budding very early?

Iowa State University horticulturists assure us that native species, at least, will be fine. In some cases, what a close observer is spotting is not a leaf bud. Rather, it is a fairly inconspicuous flower bud that will be followed later by normal leaf budding.

Obviously we cannot control the weather. However, some concerns about trees justify our attention and action. For example, anyone who is hoping to save an ash tree should be in touch with a professional arborist to plan prophylactic treatment.

Additionally, there is still a little time for pruning. Essentially there are three good reasons to prune shade and ornamental trees:

1. Safety ? For example, it may be advisable to prune away a branch overhanging a children?s play area or walkway.

2. Tree health ? Trees do best when their crowns are opened up to allow better light penetration and air movement. Letting winds blow through tree crowns rather than against them helps to limit storm damage.

3. Aesthetics ? Sometimes a tree develops unevenly and simply looks bad. Careful pruning can turn an unattractive tree into a positive landscape feature.

When pruning, it is important to respect the tree?s natural growth patterns. Cut back to the main trunk, to the base of a branch, or above a bud. Do not cut in the middle of a branch or twig. Do not leave a stub, but do leave in place the branch collar, or slight swelling, which provides a natural chemical zone helping to prevent decay. In other words, you do not want either a cut flush with a tree?s trunk or a stub sticking out a couple of inches.

Do not remove more than 25 percent of a tree?s live crown in a single year. Even if pruning has been sadly neglected, removing too much all at once will endanger the tree. A healthy tree should have a single leader and branches coming off the trunk at wide, not tight, angles.

Above all, never top a tree. Few actions have more aesthetically displeasing consequences. In addition, topping is very harmful to a tree?s health.

For most trees, the months of January, February, and March are best for pruning. The exception is spring-flowering species. Pruning them now will not be harmful but will remove potential blooms for this year. Of course, dead branches may be removed at any time.

Be sure to use clean tools properly scaled to the task at hand. Hand pruners, loppers, and pruning saws are all useful. If a pruning task calls for use of a chain saw, then it is a job big enough for a professional arborist.