Berberis thunbergii DC.

Japanese Barberry

Category
Shrub

Similar Species May be confused with the following native and/or non-native species. Landscape Alternatives lists native horticultural substitutes	Berberis canadensis Landscape Alternatives

Description

Height

This multi-branched dense shrub grows to 8.2 feet (2.5 m). Seedlings may grow 2-4 feet in one season.

Leaves

The semi-evergreen leaves are alternate, or grow in alternate clusters. They are entire, and 0.4-1.2 inches (1-3 cm) long. Leaves are bright green to burgundy, and wedge-shaped at the base.

Stems

Twigs are brown, three-ridged downward from the node, with simple thorns. Inner bark and wood are yellow.

Flowers

Flowers are solitary or in umbel-like clusters, corolla yellow, 0.3-0.4 inch (8-10 mm) broad. Blooms March-April.

Fruits

Berries are red, ellipsoid to globular, 0.3-0.4 inch (8-10 mm) long, and often present through winter. Fruit matures May-September.

Images

Photo: Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
More images of Berberis thunbergii

Life History

Japanese barberry poses a significant threat to natural areas due to its popularity as a landscape shrub, ability to tolerate full shade, and the dispersal of its prolific seeds by birds. It belongs to the Berberidaceae (Barberry) family, which is represented by one genus in our area.

Japanese barberry reproduces from prolific seeds, rhizomes, or layering. Seeds have a germination rate as high as 90%, and are distributed by birds including ruffed grouse, bobwhite, pheasant, and wild turkey. Because barberry is shade tolerant, an extensive population can become established in a short time under a closed forest canopy. Severe drought or extreme winters have little effect on overall mortality or seed production. Deer avoid barberry while often browsing surrounding vegetation, which may effectively increase barberry's competitive advantage.

Habitat

Barberry tolerates a variety of habitats from damp lowlands to dry roadsides and waste places. Populations do not expand rapidly into oak-dominant forests or on extreme north-facing slopes. Because it is widely dispersed by the nursery industry, barberry has the potential to impact most natural area ecosystems throughout Tennessee.

Origin and Distribution

Barberry was introduced to the United States in 1864 as an ornamental. It is prevalent in the northeastern states, but can be found from Nova Scotia and Michigan to North Carolina, Missouri, and throughout Tennessee. It continues to be a popular landscape plant with several varieties sold to the public. Other states where invasive: CT, DC, DE, IN, KY, MA, MD, ME, MO, NC, NH, NJ, NY, OH, PA, RI, VA, VT, WI, WV. Federal or state listed as noxious weed, prohibited, invasive or banned: CT, MA.

Sources: Information on this plant page derived primarily from the Tennessee Management Manual.

Management Recommendations

Mechanical Controls

Hand Pull: This method of control is effective for small populations of Japanese barberry, since plants pull up easily in most forested habitats. Hand-pulling is an extremely effective method of reducing population and seed productivity; this can be done during most of the year. Barberry is especially easy to see in the winter and early spring before deciduous plants leaf out. If plants have fruit present, they should be bagged and disposed of to prevent seed dispersal. Care should be taken to minimize soil disturbance.

Mowing/Cutting: This method is appropriate for initial small populations or environmentally sensitive areas where herbicides cannot be used. Repeated mowing or cutting will control the spread of Japanese barberry but will not eradicate it. Stems should be cut at least once per growing season as close to ground level as possible. Hand-cutting of established clumps is difficult and time consuming due to the long arching stems and prolific thorns.

Herbicidal Controls

Foliar Spray Method

This method should be considered for large thickets of barberry where risk to non-target species is minimal. Air temperature should be above 65°F to ensure absorption of herbicides.

Glyphosate: Apply a 2% solution of glyphosate and water plus a 0.5% non-ionic surfactant to thoroughly wet all leaves. Use a low pressure and coarse spray pat-tern to reduce spray drift damage to non-target species. Glyphosate is a non-selective systemic herbicide that may kill non-target partially-sprayed plants.

Triclopyr: Apply a 2% solution of triclopyr and water plus a 0.5% non-ionic sur-factant to thoroughly wet all leaves. Use a low pressure and coarse spray pattern to reduce spray drift damage to non-target species. Triclopyr is a selective herbicide for broadleaf species. In areas where desirable grasses are growing under or around Japanese barberry, triclopyr can be used without non-target damage.

Cut Stump Method

This control method should be considered when treating individual bushes or where the presence of desirable species precludes foliar application. Stump treatments can be used as long as the ground is not frozen.

Glyphosate: Horizontally cut barberry stems at or near ground level. Immediately apply a 25% solution of glyphosate and water to the cut stump, covering the outer 20% of the stump.

Triclopyr: Horizontally cut barberry stems at or near ground level. Immediately apply a 25% solution of triclopyr and water to the cut stump, covering the outer 20% of the stump.