Published November, 2013

Most horse farms sport trees along paddock fencerows, near barns, and in pastures. While many trees are planted for shade or aesthetics, other woody (and often undesirable) plants frequently encroach from surrounding fields. Additionally, several non-native invasive species grow throughout Kentucky, and these species can dominate an area to such an extent that desirable plants cannot survive. Regardless of the circumstances, property owners should remove undesirable trees and other woody plants.

Trees, shrubs, and vines are perennial plants that reproduce primarily from roots. Any attempt to control these plants must also address controlling the roots, either by digging and removing them or by killing the root buds with herbicides. Tree control is accomplished by cutting and treating the stump with herbicide, treating the tree foliage with herbicide, or by treating the basal area (lower 18 inches) of smaller trees with a diameter less than 2 inches. Woody vines (trumpetcreeper) and bushy plants such as blackberry and multiflora rose are controlled more easily with foliar herbicide treatments because the multiple stems might be too numerous to treat when cut. Trees and shrubs with a diameter greater than 1 inch will need to be removed by cutting the plant at the ground level. Because the tree will be removed, there is no need to spray it with herbicide before cutting. However, treat the stump with herbicide to prevent sprouting. With many tree species, more stems will occur the year after cutting if a sprout-prevention herbicide treatment is not instituted.

Invasive Honeysuckle

The most serious tree species throughout much of Kentucky are the bush honeysuckles that were introduced as an ornamental plant and wildlife habitat plant because of the bright red berries that remain on the plant well into late fall and early winter. Birds eat the berries and distribute seeds widely, which results in fencerows comprised of very dense stands. Eventually, the honeysuckle bushes will destroy the fence.

So how can you control bush honeysuckles? Several techniques are effective but all require diligence and hard work. Seedling plants 12 to 15 inches tall are easily hand-removed. However, once the plants reach 24 to 36 inches tall, they have established a strong root system and are difficult to remove by hand. Treating foliage of plants up to 4 to 5 feet tall with herbicides is effective if done after complete foliage has developed. Honeysuckle bushes taller than 5 feet are challenging to treat because much of the foliage is above head height. Because the larger bushes will need to be removed from the fencerow by cutting, the preferred control method is to cut the tree and then treat the stump to prevent sprouting.

Cut Stump Treatments

This technique is used after cutting a tree as close to the ground as possible. The purpose is to eliminate or reduce the number of sprouts from the cut surface. Immediately after cutting (less than 10 minutes), remove the sawdust and treat the outer edge of the stump with a water/herbicide mixture (e.g., 50% water/50% glyphosate). If you do not treat the cut stump immediately and before it has dried, use an herbicide/basal oil mixture, such as 25% triclopyr ester (Remedy Ultra or others)/75% basal oil. For trees wider than 4 inches, treat only the outer edge of the stump with the herbicide mixture. The outer edge contains the living tissue in which the herbicide will be translocated downward. With smaller diameter trees it is easier to treat the entire cut stump.

There are numerous products available that prevent sprouts, but it is imperative to follow the product label directions. Failures that occur are usually because people use herbicide concentrations less than suggested on the label or they wait too long to apply the herbicide to the stump. Glyphosate products are readily available, inexpensive, and safe to surrounding plants. But all glyphosate products are not created equal—the amount of glyphosate that a given product contains can range from less than 10% to 52%. For cut-stump treatments to be effective, the product needs to contain at least 41% glyphosate. A mixture of 50% glyphosate and 50% water is required. Remember, this is not the time to skimp on the rate, particularly considering the time you have already invested in cutting the honeysuckle. Add a colorant to the mixture to make it easier to determine which stumps were treated.

Farm supply stores can help you choose a glyphosate product that meets the criteria described above. Also, you can contact your local County Extension Agent for Agriculture and Natural Resources in Kentucky for specific information.

William W. Witt, professor emeritus in University of Kentucky’s Plant and Soil Sciences, provided this information.