Issue: October 25, 1999

Removing large tree saplings near foundation and in hedges

I have some fairly large trees that have come up from seeds in my hedges and are near the house. I canít dig the roots out without damaging the shrubs or the perennials in the flowerbed near the house. How can I kill the trees?

It is better to pull these tree seedlings as small saplings, but sometimes they get large before we decide to intervene, or we buy a home with the oversized weeds already well established.

In some cases, just cutting the tree as close to the ground as possible will be sufficient to kill the tree. If the tree is young, or a species that forms sprouts from the stump, you may find it necessary to ìweed outî the sprouts for a year or two. That is, cut or pull the sprouts as soon as they develop, and donít allow them to become large. By removing the sprouts as they form, you prevent them from developing enough to begin storing food reserves in the roots (feeding the roots). Each time the sprouts form, food reserves must be withdrawn from the roots. By allowing withdrawals but preventing deposits in this food bank in the roots, you will bankrupt the root system and it will die.

Some trees will produce sprouts in the lawn. These sprouts develop from the roots. Again, removal of the sprouts to bankrupt the root system will eliminate the problem in time. It may take a while, but will be effective. If the original tree remains standing, however, sprouts will continue to be formed.

To hasten the bankruptcy of the root system, you may choose to use chemicals which translocate into the roots killing them. This process may not kill all the roots, but should kill more than the simple removal of trunk or root sprouts, speeding the demise of the roots. There are several products which may be used and are labeled for this purpose at garden centers and nurseries. They are called ìbrush and stump killers.î Some other herbicides, such as the glyphosate based herbicides and some of the broadleaf herbicides intended to kill broad leafed weeds, are also labeled for this purpose. Ask your local nurseryman for recommendations and read the label on the container before purchasing the product to see that it will serve your purpose.

It is possible, often preferable, to use these products while the tree is still standing so that the tree itself may assist in moving the product into the root system. Once the tree is cut, downward movement from the leaves to the roots is eliminated, and movement from the trunk to the roots is minimal. Applying the herbicides according to directions, while the tree remains standing, allows maximum effectiveness of the product. Some of these may be applied as ìfrillî applications to notches cut shallowly through the bark. This minimizes the environmental impact of the chemical since it is not sprayed into the air or applied to the soil where it may affect other plantings.

Once a tree has been killed, or if it is cut while still living, use caution. If the tree is near a home or other structure, it may be wise to hire an insured, or bonded, tree care professional to minimize the likelihood of damage to the structure. You may be able to remove smaller trees yourself, but remember that even a small tree will be surprisingly heavy and can harm you or the structure. If the tree is killed before removing it, donít leave it standing a long time if it is near traffic ways or structures. The dead tree will fall in time and can do damage. You should remove it or have it removed so that it will fall in a manner that will do no damage.

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!