Japanese Barberry is a thorny shrub typically growing 2-3 feet tall, and similarly wide. It can grow in light or shade, and can dominate forest understories. It produces small berries that turn red in late summer/fall. One easy way to identify barberry is to break off a branch, and look at the color of the wood. Barberry has a very distinctly yellow wood. If the branch you broke off looks like normal wood, it probably is not Barberry.