Japanese Knotweed is a herbaceous perennial plant that can grow over 10 feet tall. It has distinctive shield (some say heart-shaped) leaves with a pointed tip, growing in a zig-zag formation along branch. The canes are hollow, bamboo-like stems that are green speckled with red/purple. These usually form from the "Crown" a large brown mature clump of Rhizome protruding from the ground. During the growing season, which typically spans from early spring to late autumn, the plant exhibits vigorous growth, with new shoots rapidly emerging from the ground and forming dense stands. In late summer large stands are formed with clusters of creamy flowers. During winter the above ground growth "dies back" leaving brown brittle canes.
The plant's underground system is equally formidable. Its extensive network of rhizomes can spread up to 7 meters horizontally and over 3 meters deep. These rhizomes can lie dormant in the soil for several years, making the eradication of Japanese Knotweed a challenging task.