Three spear thistle plants (Cirsium vulgare), also known as bull thistle, begin to bloom in Snohomish, Washington.

- Image ID: H683GB
Kevin Ebi / Alamy Stock Photo
Image ID: H683GB
Three spear thistle plants (Cirsium vulgare), also known as bull thistle, begin to bloom in an open field near the Snohomish River in Snohomish, Washington. The spear thistle is native through most of Europe, Western Asia and northwestern Africa and is the national flower of Scotland. It has been introduced to most other continents and is considered an invasive weed in several U.S. states and Australia.