Bull thistle (Cirsium vulgare), also sometimes called spear thistle, Fuller's thistle, and lance-leafed thistle, is a biennial weed found in almost every state and territory in the USA ...

The Minnesota Department of Natural Resources provides detailed recommendations for reporting invasive species. Bull thistle (Cirsium vulgare) is a biennial herbaceous plant (a type of bull thistle) ...

A handsome biennial that rises to a metre in height, the spear thistle bears spiny stems and pinnately lobed, pointed leaves. Pinkish-purple thistle flowers bloom singly or in clusters from midsummer ...