Perennial Knotweeds
The invasive knotweeds in Wisconsin are herbaceous perennials with a shrub-like appearance. They have multiple, hollow, arching stems in clumps that resemble bamboo. Stems have swollen nodes. Leaves are alternate and oval-shaped with pointed tips. Clusters of tiny white flowers arise along the stems in late summer and mature into flat seeds.
To view or download a PDF version of this page, click here.
Look Alikes
The perennial knotweeds look very similar to each other but are distinct from other species.
Resource Table
| Classification | Common Name | Scientific Name | Other Scientific Names | Factsheets | Statewide Distribution Map | National Distribution Map | Look-Alike Species |
|---|---|---|---|---|---|---|---|
| Prohibited | Bohemian knotweed | Fallopia x bohemicum | Fallopia x bohemica, Polygonum bohemicum | Factsheet 1 Factsheet 2 | State Map | National Map | |
| Prohibited | Giant knotweed | Fallopia sachalinensis | Polygonum sachalinense | Factsheet 1 Factsheet 2 | State Map | National Map | |
| Restricted | Japanese knotweed | Fallopia japonica | Polygonum cuspidatum | Factsheet 1 Factsheet 2 | State Map | National Map |