Japanese Barberry Invasive Species Profile
Japanese barberry (Berberis thunbergii) is a small to medium, dense shrub that was originally planted as hedges in landscaping but has spread to native habitats. Japanese barberry is capable of changing soil characteristics in order to help itself outcompete native plants and also has early spring leaf emergence that allows it to shade out any nearby competitors. The native Midwestern barberry Berberis Canadensis and the introduced Berberis vulgaris were successfully eliminated through a federal eradication program because they are able to host black stem rust, which kills small grain crops. Japanese barberry is not a host for this agricultural pest so efforts to eliminate it due to its invasive nature have been less systematic and efficient.
Habitat: Woodlands, trails, roadsides, fencerows, pastures, bottomlands, and highly disturbed areas
Hardiness: Zone 4
Mature Shape: Shrub
Height: 2-8 feet
Site Requirements: Shade tolerant; grows in various soil types but does best in well-drained soil
Leaves: simple, alternate, oval, untoothed with elongated petioles, 0.5 to 1.5 inches long; grow in clusters; turn yellow, orange, red, or purplish in the fall
Flowering Period: May
Japanese barberry twigs are ridged with spines. Newer twigs and stems turn reddish in the winter and become gray as they age. Inner bark is yellow on the branches and roots.
Flowers are one-third of an inch wide and are yellow. They can be single or can grow in small clusters of 2-4 with stems coming from a single point. Japanese barberry produces small, bright red, egg-shaped berries which remain on the plant even after the leaves have fallen.
Control Methods
Use of Japanese barberry and other invasive species in landscaping contributes to their spread into natural areas. Avoiding the use of these species is the first step to helping control their invasion.
In addition to spreading through seed dispersal, Japanese barberry is able to form rhizomes (underground horizontal stems) and spread via roots so it is necessary to remove all connecting roots when digging the plant up. Once large plants are removed, regular mowing where possible can be effective. Spring prescribed fire can also be used for control. Even after plants have been removed treatment may have to be continued for a few years as seeds sprout. See our Chemical Control of Unwanted Vegetation article for specific herbicides and application methods.
