Whatcom County WA
Bohemian knotweed
Polygonum x bohemicum

Bohemian knotweed (Polygonum x bohemicum) is an invasive plant. It is a native of Asia and was first detected in Washington in 1986.

This common invasive knotweed is a hybrid between giant and Japanese knotweed and shares characters of both parent species. It was introduced as an ornamental in its own right but has become very widespread. This plantgrows 8 to 12 feet in shrubby clumps and spreads mostly by stem and root fragments. It is usually found in disturbed areas such as flood zones and roadsides.

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