Spotted knapweed

Centaurea maculosa, the spotted knapweed, is a species of Centaurea native to eastern Europe. This short-lived perennial usually has a stout taproot, pubescent stems with wooly or cobwebby hairs when young. The erect or ascending plant stems grow 20 to 150 cm tall. It grows on stream banks, pond shorelines, sand prairies, old fields and pastures, roadsides, and along railroads, and many open, disturbed areas. While this is an invasive species, the unusual flowerheads make it a welcome sight to those who worry less about invasive species spread by humans and are more interested in seeing beautiful plants. Apparently, is should be treated with two varieties as (Centaurea stoebe var. stoebe and var. micranthos (S.G. Gmel. ex Gugler) Hayek.