Bermudagrass Johnsongrass Medusahead Quackgrass Field Bindweed Hoary Cress Diffuse Knapweed Russian Knapweed Spotted Knapweed Squarrose Knapweed Purple Loosestrife Perennial Pepperweed Leafy Spurge Yellow Starthsitle Canada Thistle Musk Thistle Scotch Thistle Dyer's Woad Back to main weeds page   Squarrose Knapweed Centaurea virgata   Rosette The rosette and stems have deeply lobed leaves. Adult This long-lived perennial grows 12 to 18 inches tall. Flower Flowers are rose to pink. It is often confused with diffuse knapweed, but differs in that the toothed flower bracts are curved outward, and are not laterally toothed. Bloom occurs in early to mid-summer. Squarrose knapweed is a native plant of the eastern Mediterranean area. It is very competitive on rangelands. Knapweed releases a chemical substance reducing competing vegetation. Back to main weeds page   Buffalobur Common Burdock Camelthorn Goatsrue Jointed Goatgrass Poison Hemlock Black Henbane Houndstongue Blue-Flowering Lettuce Western Whorled Milkweed Silverleaf Nightshade Yellow Nutsedge Puncturevine Russian-Olive Saltcedar St. Johnswort Bull Thistle Dalmatian Toadflax Yellow Toadflax Velvetleaf