Japanese Barberry

Berberis thunbergii

japanese barberry understory invasion
 Image credit: Leslie J. Mehrhoff

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 (1-2 cm), oval-shaped leaves with smooth margins, green during the summer with a fall color of bright red to purple. Some ornamental varieties maintain 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 WiGL or MISIN.

 

KISMA Management Practices

Japanese barberry is one highly aggressive invasive species. It produces large amounts of seeds and has the ability to regenerate if parts 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 very important 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 tree roots. That said, many times the roots may spread quite far and require some digging to completely remove.

 

Native Alternatives 

In place of 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 are great since they fill up disturbed sites and stop invasives from establishing there.

 

japanese barberry leaves
(image credit: Leslie J. Mehrhoff) Japanese barberry leaves
Japanese barberry berries
(image credit: Chris Evans) Japanese barberry berries 
Japanese barberry flower

(image credit: Leslie J. Mehrhoff) Japanese barberry, purple variant, with flowers 

young Japanese barberry

(image credit: Richard Gardner) young Japanese barberry plant 

Sources

“Japanese barberry (Berberis thunbergii).” MISIN, 2020

“Barberry alternatives.” NMISN, 2017

"Chris Evans, Richard Gardner, and Leslie J. Mehrhoff" Bugwood.org