Now is the time of year to get a handle on pesky landscape and forest maintenance problems, including unwanted woody species.
Dr. Larry Tankersley, a forestry specialist with University of Tennessee Extension, says late winter and early spring are the perfect times to apply basal sprays to manage forested areas. “Late winter and early spring are usually recommended for basal spray application of herbicides as leaves are off and won’t inhibit spraying the stem,” he said.  “Also prominent spray ingredients include esters, which are volatile during higher temperatures.”
Basal sprays are herbicide-oil-penetrant mixtures sprayed or daubed onto the lower portion of woody stems, usually applied with a backpack sprayer or wick applicator. Tankersley says basal sprays offer an alternative herbicide application method for controlling woody stems that are less than about 6 inches in diameter, larger if the species is particularly susceptible to the herbicide. The forester says applications should be made before bark becomes thick, corky, and furrowed.
“The treatments are especially useful on species with smooth juvenile bark such as ailanthus, mimosa and red maple,” he said.  He also emphasized that the treatments are also useful for bush honeysuckle and the regionally invasive nuisance shrub privet. Tankersley recommends treating “clumps” or clusters of multiple small stems.

Full basal treatments require that the lower 12 inches to 20 inches of the target plant be completely wetted on all sides with an oil-based spray mixture. Herbicides that are soluble in oil (mainly the ester formulation of triclopyr) are mixed with commercially available crop oil. Some herbicides are sold ready-to-use with these ingredients.

For more information on basal spraying Tankersley recommends the USDA Forest Service publication, “Nonnative Invasive Plants of Southern Forests, a Field guide for Identification and Control.” It is available online at

For more information about forestry management issues, contact your local county UT Extension office or visit the UT Extension publications website:
Additional information may also be available at the national extension website:

UT Extension provides a gateway to the University of Tennessee as the outreach unit of the Institute of Agriculture. With an office in every Tennessee county, UT Extension delivers educational programs and research-based information to citizens throughout the state. In cooperation with Tennessee State University, UT Extension works with farmers, families, youth and communities to improve lives by addressing problems and issue at the local, state and national levels.


Dr. Larry Tankersley, UT Extension Forestry Specialist, 865-974-7977


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