Spotted Knapweed

Spotted knapweed is found primarily in the dry, gravel soils of roadsides, parking lots, railroad beds and quarry areas in Calumet County. Spotted knapweed commonly grows to 3-4 feet, with the majority of stem growth occurring in June. Single thistle-like pinkish flowers are about ¾ inch in diameter. Spotted knapweed reproduces solely by seed, so the plants need to be controlled before going to seed. The flowers bloom from July through August, for a few days each. The heads reopen after about 20 days to scatter the nearly 1000 seeds per plant. Mow this plant in late June before it flowers and forms seeds. For additional information, visit http://dnr.wi.gov/invasives/fact/pdfs/knapweedFactsheet.pdf