Knotweed Identification

Japanese knotweed growing on a roadside

Browse our knotweed slides below to learn how to identify these invasive plants before they take over your yard, park or garden. These plants (with the exception of Himalayan knotweed) are destructive, breaking apart asphalt and entering homes through the foundation. Check out the Knotweed! app to learn more about all four species of knotweed: Japanese, giant, Bohemian (the hybrid of Japanese and giant) and Himalayan (uncommon).

Note: Japanese knotweed is on the list of 100 top invasive species in the world. 

Japanese Knotweed
(Fallopia japonica)

Giant Knotweed
(Polygonum sachalinense)

Bohemian Knotweed
(Polygonum x bohemicum)

Himalayan Knotweed
(Polygonum polystachyum)