Brown knapweed is native to Europe and was probably introduced to North America as an ornamental species.Brown knapweed can invade open forests, grasslands, and prairies. It can out-compete native vegetation, reducing biodiversity and available forage species.Brown knapweed flowers are 15-25 cm wide. Bracts usually have a distinctive papery margin and are light brown called bracts, which are modified leaves underneath the flower petals. The leaves are lance-shaped or shallowly lobed and become progressively smaller up the stem. The fruits usually don't have a plume or bristles.In the first year of growth, brown knapweed only has leaves on the ground (in a rosette). It grows a stalk and blooms in the second and subsequent years. Brown knapweed grows up to 150 cm tall. The stems are rigid and may have purple stripes.It can hybridize with black knapweed, which creates plants that look slightly different from either parent species.