Issue: August 2, 2003

Broken branch

I had a large branch break off a tree from heavy winds. The tree is otherwise in good health. Do I need to treat the exposed cut on the tree or can I just leave it to weather?

You can cut the branch cleanly just outside the "branch collar" (the slightly swollen area where the branch meets the trunk). Do not cut inside the branch collar unless the bark ripped as the branch fell. If that occurred, then only cut to create a clean (rather than ragged) wound. Do not use pruning sealer materials. They will do more to help disease organisms that will grow better in the protected, humid environment below the sealer. An unpainted wound (especially one outside the branch collar) will be "compartmentalized" by the tree to prevent entry of disease organisms and insects into the trunk. Some people want to put a bandage on the wound, but this isn't necessary. If you need to do so for your own sake (not the tree's), you can use a thin white latex (water-based) paint. Dark paint or pruning materials will become too hot in sunlight and damage the tender tissues the tree produces to close the wound, so don't use dark colors.

Globe willow branches dying

I live in the South Valley near one of the ditches. My problem is that I have two very beautiful globe willows in my front yard, and one of them is dying. They are in the middle of my lawn so they get a lot of water. They are close to nine years old and have been doing great until about a month ago. There are at least 8 to 10 big branches turning brown and more seem to be following that pattern. I sprayed at the beginning of summer for aphids that occur every year, so could you please give me some advice as soon as possible. Dora L. Albuquerque

When you say the trees are well watered, I assume you irrigate by flooding your yard from the ditch. Trees do well under that situation except in the winter when the ditch is not flowing. From what you describe, I think your problem developed during the winter. Trees need to be irrigated once a month in the winter, especially in late January and February. It was very dry last winter. Injury that develops as a result of winter drought appears as dying branches in the summer. Stressed trees attract borers, which may also be doing damage. If you find that borers are present, take a sample to your local County Extension Service office to have the insects identified. The Extension agent should then be able to tell you the steps you should take to prevent further damage by borers. In the meantime, be sure the trees are watered deeply once every two weeks in the growing season and once a month in the fall and winter. You can prune dead and dying branches from the trees. This will allow you to remove any borers from the vicinity of the tree and reduce re-infestation as the borers mature.

Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, email: desertblooms@nmsu.edu, office: 505-865-7340, ext. 113.

For more gardening information, visit the NMSU Extension Horticulture page at Desert Blooms and the NMSU Horticulture Publications page.

Send gardening questions to Southwest Yard and Garden - Attn: Dr. Marisa Thompson at desertblooms@nmsu.edu, or at the Desert Blooms Facebook.

Please copy your County Extension Agent and indicate your county of residence when you submit your question!