Japanese Barberry or the Berberis thunbergii

Japanese Barberry(Berberis thunbergii) was brought to the United States from Asia in the late nineteenth century to originally be used as an ornamental, unfortunately it has escaped and naturalized  and can be found anywhere as far as Nova Scotia, south to North Carolina, and west to Montana. It is a threat to open and second-growth forests, it can eventually grows thick enough to crowd out native understory plants.Which makes traversing through dense patches of barberry can be difficult and even painful. It is spread by Birds who eat the red berries. It is recommended to be mechanically removed and can be distinguished by how early its leaves begin to bloom in the spring.

Work Citied:
http://www.nps.gov/plants/alien/fact/beth1.htm
http://en.wikipedia.org/wiki/Berberis_thunbergii
http://commons.wikimedia.org/wiki/File:Berberis_thunbergii_purple_hedge.JPG
http://plants.usda.gov/java/profile?symbol=beth