Perennial sowthistle identification and control
Perennial sowthistle, a Class C noxious weed, is an herbaceous perennial that grows 1.5-6 feet tall in farms, meadows, forests, disturbed areas, and a variety of other settings. It has hollow stems containing a milky juice, alternate leaves with spiny edges, and bright yellow, 1.5-inch-wide flower heads. This weed reproduces via seeds and rhizomes.
Additional information on perennial sowthistle
- Washington State Noxious Weed Control Board (external link)
What to do if you find this plant in King County, Washington
If you wish to control perennial sowthistle, our program staff can provide site-specific advice on how best to remove it. The county isn't currently tracking locations of this species.
Report perennial sowthistle in King County, Washington
- Please notify us through our online infestation form
Locate perennial sowthistle in King County, Washington
- Use our interactive noxious weed map and search for perennial sowthistle