Contact information
For information on Lakes in Wisconsin, contact:
Division of Water
Bureau of Water Quality
Aquatic Invasive Species Contacts

Giant knotweed (Polygonum sachalinense) - W. Bigelow St.

Verified and Vouchered
Date First Found

Giant knotweed (Polygonum sachalinense)

About Giant Knotweed

Giant knotweed is a herbaceous perennial that can reach 9’ tall with erect, hollow stems that resemble bamboo. The stems are smooth and arching with swollen nodes and twigs that zigzag from node to node. Giant knotweed invades riparian areas where it prevents streamside tree regeneration. It is often found in floodplain forests, disturbed areas, roadsides, and vacant lots. Plants form dense stands that crowd and shade out native vegetation.