Control the Spread of a Black Locust Tree

The black locust tree is a fast-growing tree that can reach heights of up to 100 feet. In addition, has underground root suckers that can extend a long distance away from the tree, allowing for easy propagation. Seedlings and sprouts grow rapidly, which has led to a problem with the spread of these trees.

The wood from the tree is the most durable wood in North America, and is commonly used to construct fence posts, ladder rungs, and other objects.

Controlling the Spread

Black locust is difficult to control because it grows rapidly and exhibits clonal spread. Some methods of control include mowing and burning of the trees, which has not worked to curb the plant's growth. Because the plant can spread vegetatively, this method only has temporary results.

Chemical control is the most effective method at the moment, although it also has limited success. Follow-up treatment is almost always required for all control methods.


Cutting is another way to slow the spread of the black locust tree. Repeated cutting during the growing season involves a lot of work, but can be quite effective. When cutting the tree, all stems must be cut, including new stems that appear after the first cutting. This method of treatment has to be repeated for several years to achieve the right amount of control.

Annual haying is another method to control first year seedlings and prevent the unhindered spreading of the tree in prairie zones.


Applying herbicides to the basal bark on live standing trees is another method of control. This method works best on small trees that are thin-barked. It is less successful on larger trees. Herbicides hinder roots and stumps from resprouting if applied between mid July and the end of December. Professionals use the product Remedy at a 2% solution in diesel fuel.

All you have to do is spray the basal part of the tree about 15 to 20 inches above the ground. Make sure all basal bark areas are thoroughly covered, including the crown buds and ground sprouts. You have to spray the tree thoroughly until you notice run-off at the ground line for the spray to be effective. Apply in dry weather for optimum root control.

Garlon 4 is another effective product for basal bark treatment. Avoid using any of these chemicals if rain is in the forecast for the following 1-4 days. Runoff can cause harm to species in the area that you don't want affected by the herbicide.

Don't use pelleted herbicides because this causes leaching, which could affect native woody plants. In addition to the sprays mentioned above, a number of sprays are available specifically for foliage or stump treatment. However, these products usually require more treatments after the initial application. The first two methods only require one application to be effective.

One such product is called Krenite. It is a non-volatile, contact brush herbicide that you apply as a spray to leaves. It is best to apply this herbicide two months before fall coloration begins (July to September).