Japanese Barberry (Berberis thunbergii)

Taxonomy

Domain	Eukarya
Kingdom	Plantae
Phylum	Magnoliophyta
Class	Magnoliopsida
Superorder	Ranunculanae
Order	Ranunculales
Family	Berberidaceae
Genus	Berberis

Scientific Name

Berberis thunbergii

Common Name

Japanese barberry

Miller, J.H., E.B, Chambliss, N.J. Loewenstein. 2010. A Field Guide for the Identification of Invasive Plants in Southern Forests. General Technical Report SRS-119. Asheville, NC. United States Department of Agriculture, Forest Service. 126 p.

Plant

Tardily deciduous, compact and spreading shrub, 2 to 4 feet (60 to 120 cm) in height and slightly wider, occasionally 6 to 8 feet (1.8 to 3 m) in height. Multiple alternate, slender and brown stems bear single slender spines at nodes, along with tufts of small paddle-shaped leaves ranging from green to reddish and turning orange and golden to crimson in early winter. Tiny, dangling clusters of white flowers in spring yield red, fleshy, oblong berries. Roots shallow, yellow inside as are stems. The plant traits are variable due to numerous cultivars that are still being sold and planted.

Stem

Twigs slender, reddish brown to gray, ridged to varying degrees, a single sharp spine to 0.6 inch (1.5 cm) long at each node, below a stubby, conelike stacked bud (evident in winter). Stems sometimes wavy in appearance owing to numerous alternate nodes. Alternate branching with bark becoming irregularly furrowed, light gray to tan, with scattered, stacked buds remaining.

Leaves

Alternate in tight clusters, spatulate (paddle shaped) with entire margins and bases narrowing to the stem, with rounded or faintly pointed tips, variable due to cultivars, 0.5 to 1.5 inches (1.2 to 3.7 cm) long. Blue green to green to reddish above and pale to whitish below, turning orange and golden to red and crimson in winter. Appear early and remain late.

Flowers

April to May. Dangling singly or in small clusters from most nodes, 6 white to yellowish-white to yellow petals, 0.2 to 0.3 inch (5 to 6 mm) wide with yellow centers.

Fruit and seeds

May and maturing by October, remaining until March. Dangling, eggshaped berries, red and shiny, fleshy, 0.3 to 0.4 inch (8 to 11 mm) long. Each containing 1 brown, pitted seed, oblong, 0.08 to 0.20 inch (2 to 5 mm) long.

Ecology

Forms dense infestations under forest canopies, but prefers partial shade of edges, to exclude other plants. Seeds are dispersed by many wildlife species. Deer do not browse this species, resulting in release from surrounding browsed vegetation. Infestations intensify by root sprouts and rooting of drooping stems. Seeds remain viable for up to 10 years in the soil.

Resembles

Resembles both the nonnative invasive common or European barberry (B. vulgaris L.) and the native American barberry (B. canadensis Mill.), while both have finely bristled leaf margins. Also resembles a rare escaped wintergreen barberry (B. julianae C.K. Schneid.) in the mountains that has leathery, evergreen leaves.

History and use

Native to Japan and introduced into the U.S. as an ornamental in the mid-1870s. Numerous cultivars widely sold and planted with varying amounts of fruit production.

Distribution

Found as scattered plants and a range of infestation densities in GA, SC, NC, TN, KY, and VA.

Management strategies

Do not plant. Remove prior plantings, and control sprouts and seedlings. Bag and dispose of fruit in a dumpster or burn.
Treat when new plants are young to prevent seed formation.
Cut or mulch when fruit are not present.
Minimize disturbance within miles of where this plant occurs, and anticipate wider occupation when plants are present before disturbance.
Manually pull and tree wrench when soil is moist, ensuring removal of all roots.
Burns hot when green to topkill small to medium-sized stems.
Readily eaten by goats and sheep.

Recommended control procedures

Thoroughly wet all leaves with a glyphosate herbicide or Garlon 3A as a 2-percent solution (8 ounces per 3-gallon mix) in water with a surfactant.
Cut large stems and immediately treat with one of the following herbicides: a glyphosate herbicide or Garlon 3A as a 25-percent solution (3 quarts per 3-gallon mix). ORTHO Brush-B-Gon, Enforcer Brush Killer, and Vine-X are effective undiluted for treating cut-stumps and available in retail garden stores (safe to surrounding plants).
Subsequent foliar applications may be required to control new seedlings and resprouts.

Images

April	April	November
October	May	April	April

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