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Let’s Get Growing with Dr. Mary Helen Ferguson

People occasionally inquire about how to kill woody vines or unwanted shrubs or trees that keep regrowing in spite of being cut back severely.

An easy option that minimizes risk to nearby plants is to make what’s called a “cut stump” treatment using an herbicide that contains the active ingredient triclopyr.

When this type of application is made, the woody stem is cut near the ground, and the herbicide is applied to the freshly cut surface of the stump. Triclopyr moves down into the roots through the plant’s vascular tissue.

A number of triclopyr-containing products are labeled for cut stump application. BioAdvanced Brush Killer Plus Concentrate, Bonide Stump-Out Stump and Vine Killer, Fertilome Brush Killer Stump Killer, Ortho GroundClear Poison Ivy and Tough Brush Killer1, Pathfinder II, and Stump Stop are examples of products that are applied full-strength, without dilution, when used in this manner. (Look for products that are 8 to 13.6% triclopyr. Some products have similar names but much lower concentrations.)

There are also products with higher concentrations of triclopyr that can be used for stump treatment after being diluted.

The phloem tissue that carries the chemical to the roots is along the inner edge of the bark. So, make sure you get the herbicide along the outer edge of the stump surface and not just in the middle.

Triclopyr-containing products will kill or damage many types of plants, so be sure not to get them on plants you don’t want to kill. Also be aware that, if the treated plant shares a root system with another plant (for example, if one is a sucker of the other, or if roots have grafted together), the herbicide can kill or damage the other plant, too.

Be sure to read and follow label instructions when using any herbicide or other pesticide.

Let me know if you have questions.

Dr. Mary Helen Ferguson is an Extension Agent with the LSU AgCenter, with horticulture responsibilities in Washington and Tangipahoa Parishes. Contact Mary Helen at mhferguson@agcenter.lsu.edu or 985-277-1850 (Hammond) or 985-839-7855 (Franklinton).