Japanese knotweed is a herbaceous perennial that can reach heights of 9' tall. Semi-woody stems are erect and hollow and resemble bamboo canes.
Leaves: Leaves are dark green and are 4-6" long.
Flowers: There are many small greenish white flowers. These flowers bloom in late summer.
Fruits & Seeds: Seeds are small, shiny, and black. They are enclosed in a winged calyx that makes them buoyant.
Roots: Robust rhizomes grow 6' deep thus creating a dense impenetrable mat.
- Japanese knotweed invades forest edges, wetlands, fields, roadsides, and urban areas. It poses a significant threat because it will eliminate vegetation and cause erosion.
- Young stems can produce new roots and shoots if buried or floating.
- Japanese knotweed is able to break through pavement and building foundations.