Japanese Barberry

Berberis thunbergii

Common Name: Japanese Barberry
Scientific Name: Berberis thunbergii
Family: Berberidaceae
Growth Form: Shrub
Native Range: Japan
Invasive Range: From Nova Scotia to North Carolina and as far west as Montana
Introduction: Japanese Barberry was brought to the Arnold Arboretum in Boston in 1875 as an ornamental. 
Description: ·Leaves: Wedge shaped. Simple. Arranged in whorls.  1-3 cm (.5-1.5 in.) long.  Turn red and orange in the fall.

·Branches: Dark brown, shiny, zig-zag. Single sharp spine at each node.  Plant can grow .6- 2m (2-6 ft.) tall. 

·Flowers: Pale yellow. Four petals. Alone or in umbrella shaped clusters of 2-4 flowers.  Appear in May. 0.5 cm (.25 in.) diameter. 

·Fruit: Red, oval. 1 cm (.4 in) long.  Persist into the winter.

Threats: Japanese barberry forms dense stands that shade out native vegetation.  Birds are highly attracted to its fruit, widely spreading the seeds.  It raises soil pH and reduces the amount of leaf litter on the ground.  It is particularly dangerous to open and second-growth forests. 
Fun Facts: Japanese barberry was originally promoted as an alternative to common barberry. Common barberry, a native plant, was used by settlers as hedgerows and to make dye and jam, but carried black stem grain rust.
English ivy on a tree
English ivy taking over a tree
leaves and fruit
Nodal arrangement of fruit and leaves