Cottonwood Sprouts

My neighbors cut down their cottonwood tree, and now I have little cottonwood sprouts all over my yard. What can I do to stop this?

It is not uncommon for cottonwood sprouts to develop from the roots, especially after the tree has been cut. Even if the stump is treated with stump killer, the roots often produce sprouts. You can mow them, but that will leave hard sticks at the level of the grass and these sticks may try to begin growing again. You can cut them with a shovel below ground level, and they may still try to grow. Finally, you have the option of applying herbicides. A systemic (translocating) broadleaf herbicide will not harm the lawn if used according to directions but will be absorbed into the cottonwood sprouts and translocated into the roots, killing more than just the stem. Some of the roots will survive so some sprouting may continue, but this will help stop the sprouts.

In any method, the important consideration is to keep the sprouts from retaining leaves. It takes energy stored in the roots as carbohydrates to produce the sprouts. The leaves produce food which is returned to the roots making additional growth and sprouting possible. Removal of the leaves soon after they are formed (by using a mower, digging with a shovel, or applying herbicides) prevents the replacement of the carbohydrates in the roots. In time these carbohydrates will be depleted and sprouting will stop. This is your objective.

Compost

If the leaves on my trees have spots on them, can I put the leaves in the compost, or will they cause diseases next year if I compost them?

We are generally taught not to compost diseased plants, but in your case I would compost the leaves. If the leaves are composted properly, the disease organisms will be killed and will not be a concern. Another consideration is that it is possible, but not likely, that the disease on the tree would affect vegetable or flower garden plants. Diseased vegetables and flowers are a greater concern because they are more likely to carry the diseases that affect garden plants.

It is possible to compost diseased plants if the disease is killed before composting. You can do this by putting the diseased plant in a black plastic garbage bag and leave the bag in sunlight. New Mexico's sunlight intensity will create sufficient heat in the plastic bag to kill the disease organisms. After a few days, it is safe to put the plant into the compost.

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!