Japanese Barberry

Berberis thunbergii

Characteristics

Japanese barberry, a woody shrub in the Berberidaceae family, is an understory invasive that can live in many different soil and light conditions. It has nitrogen containing roots (giving them a yellow color) and spiny branches.

• small, oval-shaped leaves are 1-2 centimeters in length with smooth margins. Leaves are green during the summer, turning bright red to purple in the fall. Some ornamental varieties maintain the purple color year round.
• blooms April-May, and produces small, yellow flowers singularly or in clusters
• produces red, egg-shaped berries that can be singular or in clusters along branches
• stems are a reddish brown and turn gray as they age, while roots are bright yellow inside

For more information visit Woody Invasives of the Great Lakes (WIGL) Collaborative or Midwest Invasive Species Information Network (MISIN).

KISMA Management Practices

Japanese barberry is a highly aggressive invasive species. It produces large amounts of seeds and has the ability to regenerate if segments of the root are left in the ground. Branches that make contact with the soil are also able to form roots when buried in the ground, a form of vegetative reproduction known as layering. This means it is crucial to remove all the plant material when managing barberry. Here at KISMA, Japanese barberry is one of the major species we deal with, having many sites that we return to each year to make sure new sprouts are pulled until the species is completely eradicated.

1. start by hand pulling, wearing double gloves that allow for protection from the sharp spines on the stems. Make sure to remove as much of the root mass as possible. A narrow shovel is often helpful for "leveraging" roots out of the ground as long as care is taken not to cut the stem from the root mass.
2. hang bushes from nearby trees by their roots to prevent resprouting. Hanging the plants by the roots allows the plant to dry out and die before decomposing. However, if the shrub contains berries, remove them from the site carefully and dispose of, in order to prevent further spreading of the seeds.
3. if species cannot be removed by hand pulling, use a root wrench to loosen roots and then remove with hands. If the bush is too large you may need to cut off branches in order to reach the base of the plant.

Note: All plant material should be removed safely and completely. Roots can be easily seen by their vibrant yellow color and easily told apart from other nearby tree roots. That said, many times the roots may spread quite far and require some digging to completely remove.

Native Alternatives 

In place of Japanese barberry, planting native species such as ninebark (Physocarpus opulifolius), hawthorn (Crataegus sp.), and others are great alternatives. They are better food sources for wildlife and increase local biodiversity. Also, planting understory plants like ferns and other native terrestrial plants is great since they fill up disturbed sites and stop invasives from establishing there.