Japanese barberry

Japanese barberry
(Berberis thunbergii)

A low-growing (2-3’ tall), dense, spiny shrub with small oval green leaves that turn reddish brown in fall. Plants have single sharp spines at each node and small, bright red, oblong berries.

Current invasive species rule revisions propose to regulate this species as Restricted.

Overview

Regulated areas of Japanese barberry
This species is proposed as Restricted (Orange counties)

Other names for this plant include:

  • Common names: barberry, Thunberg's barberry, Japanese berberis
  • Scientific names: Berberis thunbergii var. atropurpurea

Ecological threat:

  • Shade tolerant, drought resistant, and adaptable to a variety of open and wooded habitats, wetlands, old fields and disturbed areas.
  • It forms dense stands in natural habitats, dominating the forest understory by shading out native plants and changing foraging habits of wildlife.
  • Spreads vegetatively though horizontal branches that root freely when they touch ground.
  • Research shows infested forests have higher rates of Lyme disease carrying ticks.
  • White-tailed deer avoid browsing barberry due to the spines, preferring to feed on native plants, giving it a competitive advantage.
  • Prefers well drained soils and sunny habitats, but will survive and produce fruit in even heavily shaded environments.
  • Very invasive and widespread across Eastern United States and the Midwest.
  • Cultivars are widely planted as ornamentals.

Classification in Wisconsin: Proposed as Restricted

Restricted straight species and cultivars: Tara; Crimson Velvet; Sparkle; ‘Anderson’ Lustre Green; Marshall Upright; Erecta; ‘Bailgreen’; Jade Carousel; Red Rocket; ‘Monomb’ Cherry Bomb; Painter’s Palette; Inermis; Wild type/parent species; var. atropurpurea; ‘Bailone’ Ruby Carousel; Pow Wow; JN Redleaf; Gold Ring; Rose Glow; Kelleris; Kobold’ ‘JN Variegated’ Stardust; ‘Bailsel’ Golden Carousel; B. koreana x B. thunbergii hybrid; Silver Mile; Antares.

Species Assessment Groups (SAG) were assembled to recommend a legal classification for each species considered for NR 40. The recommendation for Japanese barberry was based upon this literature review developed by the department.

Identification

Leaves & stems: Clustered in tight bunches above spines, the leaves are simple, alternate, small, and oval to spatulate shaped (wider at the tip than the base). Leaves may be green, bluish green, or dark reddish- purple depending on the cultivar. They leaf out in early spring. Plants have single sharp spines at each node. If a stem is cut, it will reveal that the inner bark is yellow. Branches root freely when they touch the ground.

Flowers: Flowers are cream-yellow colored, bowl-shaped with notched edges and 6 petals, and small (1/3” wide). They occur individually or in small clusters of 2-4, blooming in mid-spring.

Fruits & seeds: Small, bright red, oblong berries occur on narrow stalks both singly or in clusters. Berries persist on shrub into winter. Seeds are readily dispersed by birds.

Roots: Creeping, shallow roots are tough. Interior of roots are yellow. Branches root freely when they come into contact with ground.

Similar species: European barberry or common barberry (Berberis vulgaris) is also a non-native invasive (classified as Prohibited) but has spiny, toothed leaves and flowers in a long raceme.

Distribution

Known county distribution of Japanese barberry
Counties in WI where Japanese barberry has been reported (as of June 2013). Both vouchered and unvouchered reports included.

Do you have Japanese barberry in your county but it isn't shaded on the map? Send us a report.

Control

 

Mechanical:

  • Plants can be pulled out or dug up, easiest in early spring. Remove all roots and watch for resprouts. Cutting without herbicide will result in resprouting.
  • Mow or cut larger plants before seed set if not able to remove the entire plant.
  • Prescribed burns in early spring or late fall can be effective to kill seedlings. Use this method in fire-adapted communities to prevent mortality of surrounding desired vegetation.

Chemical:

  • Foliar spray with metsulfuron-methyl, triclopyr or glyphosate.
  • Adding a penetrating oil can be effective when used as a cut-stump treatment and basal barking.

Photos

View Japanese barberry pictures in our photo gallery!

Resources

Sources for content:

  • Czarapata, Elizabeth; Invasive Plants of the Upper Midwest: an illustrated guide to their identification and control. University of Wisconsin Press. 2005. Pg. 88-89
  • Center for Invasive Species and Ecosystem Health, Invasive.org. Japanese barberry [exit DNR].

Links for More Information

Last revised: Monday December 02 2013