Basal Bark: Herbicidal Treatment

- What is a basal bark herbicide treatment?

A basal bark herbicide treatment is an effective method to control most woody plants that are less than six inches in diameter.

The herbicide mixture is applied directly to the bark of an individual undesirable plant.

The active ingredient we often recommend for basal bark applications in forest settings is triclopyr ester.

This is a systemic herbicide that is absorbed through the bark and moved to other areas in the plant.

Triclopyr works by disrupting plant growth.

Basal bark applications are effective because they use an oil carrier that can move the active ingredient through the bark and into the target plant.

You can find commercially available basal oils in either mineral or vegetable-based formulas.

Herbicides should always be mixed and applied according to the label directions.

Basal bark applications are made using a low pressure backpack sprayer with a wand and a solid cone or flat fan nozzle to wet the lower 12 to 15 inches of stem.

To properly treat a stem, wet the entire circumference of the stem including the root collar area and any exposed roots.

The herbicide mixture should be applied to the stem as thoroughly wet, but not to the point of running off.

On non root suckering species, basal bark applications can be made at any time during the year, including the winter, except when snow accumulation prevents spraying to the ground line.

Applications should also not be made right after a rain event when stem surfaces are wet.

For root suckering species such as oriental bittersweet, black locust, beech, and tree-of-heaven, basal bark applications must be done during late summer or fall, starting in July and ending in October, to maximize the herbicide moving into the root system.

For best control of root suckering species, treat all stems and suckers since some herbicides are not translocated into untreated stems.

Using an indicator dye in the herbicide mix helps you assess where you have already treated to avoid accidental duplicate treatments or skipped stems.

In a basal bark treatment, herbicide is applied directly onto the stem of a specific unwanted plant, which minimizes damage to desirable plants in the same area.

Basal bark herbicide applications can be used to control native woody forest vegetation that is undesirable because it interferes with the growth or establishment of preferred plants.

Some examples of species that may be targeted for removal with basal bark treatments include red maple, black birch, striped maple, eastern hophornbeam, and American beech suckers.

American beech parents, however, are not affected by basal bark treatments.

Basal bark herbicide applications are also an effective treatment for invasive plant control.

Because invasive shrubs tend to leaf out in spring earlier than native vegetation and keep their leaves later into the fall, they are easy to find and treat with a targeted basal bark treatment.

Japanese barberry, autumn olive, privet, buckthorns, and most other invasive shrubs can be controlled with basal bark applications.

Keep in mind that controlling plants with multiple stems requires treatment of each stem with the basal herbicide spray.

Basal bark herbicide applications are an efficient targeted option for controlling undesirable or invasive vegetation.

They reduce damage to non-target species and provide flexibility in the timing of application.

As with any herbicide application, monitor the treatment site for resprouts and new plant growth following treatment.

It is important to be persistent to ensure complete control.