Issue: June 1, 2001

• Eliminate "Chinese" elms
• Sick new tree

Eliminate "Chinese" elms

I have a question regarding what we call "Chinese elm trees" here in Albuquerque, although I'm not sure that is their real name. How can I rid my property of these trees?

The elms to which you refer are probably Siberian Elm (Ulmus pumila) instead of the true Chinese Elm (Ulmus parvifolia). Siberian elm is very common in Albuquerque and has become a nuisance. They are useful trees in areas where trees are desired but care is unavailable. Unfortunately, their profuse production of viable seeds results in elms growing where they are unwanted.

If you cut the tree, there is a good chance it will sprout from the base. Unlike the cottonwoods, it is less likely to produce sprouts from the roots over a large area. Some people have had good success with drilling holes in the stump immediately following cutting the tree. These holes are filled with any of several chemicals labeled for killing tree stumps. A more effective method is to apply the chemical in "frills" or notches made by downward cuts that go just below the bark of the tree. This region of the tree contains the phloem that carries material from the top of the tree to the roots. Chemicals applied in this zone translocate to the roots to kill the roots. There are several products available in nurseries and garden centers labeled for "frill application." The chemical is usually applied full strength in this manner of application. (Read and follow the directions on the label for best results with the chosen product.) After a few weeks, the tree may be removed. It is important not to leave a dead tree standing near homes, cars, playgrounds, traffic ways, or any other place where injury or damage could occur if the tree fell.

If some sprouts develop following application of the product to the trunk frills, foliar spray of a labeled herbicide on the newly developing sprouts should be effective in completing the elimination of the tree.

Sick new tree

My tree that I recently bought is looking sick. The leaves on the tree look burned and eaten up. What should I do?

A newly planted tree will often look as you have described because it does not have a large enough root system to provide adequate water to the new tree. As a result, the leaves dry around the edges and begin to rip and tear. As the tree establishes and develops a larger root system, this should become less of a problem. In a really windy location, the problem may remain in later years.

For now, just be sure the tree is watered about once a week. Water slowly so the water can soak in deeply and moisten the whole root ball. Don't water too often or the roots will begin to rot. The surface of the soil will dry a lot faster than the soil several inches down.

If you think it is insects eating the leaves rather than wind tattering, take some leaves to your local Cooperative Extension Service office and perhaps the Extension Service Agent can help. However, in most cases it is difficult to identify the culprit from only the leaves.

Please join us on Southwest Yard & Garden, a weekly garden program made for gardeners in the Southwest, broadcast on KRWG-Las Cruces on Saturdays at 11:30 a.m., Tuesdays at 6:30 p.m. and Thursdays at 1:00 p.m.; KENW-Portales on Saturdays at 10:00 a.m.; and KNME-Albuquerque on Saturdays at 12:00 noon, and Fridays at 2:30 p.m.

ALBUQUERQUE 2001 SPRING ROSE SHOW presented by the Albuquerque Rose Society on Saturday, June 2 and Sunday, June 3 at the Albuquerque Garden Center, 10120 Lomas Blvd., NE. Entries will be accepted from 7:30 to 10:00 a.m. on Saturday. The show is open to the public on Saturday from 1:00 to 5:00 p.m. and on Sunday from 10:00 a.m. to 4:00 p.m.

Send gardening questions to Southwest Yard and Garden, Attn: Dr. Marisa Thompson at desertblooms@nmsu.edu or at https://www.facebook.com/DesertBloomsNM/. Please include your county Extension Agent (aces.nmsu.edu/county) and your county of residence with your question!

For more gardening information, visit the NMSU Extension Horticulture page: desertblooms@nmsu.edu.

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, office: 505-865-7340, ext. 113.