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   Spotted Knapweed Centaurea maculosa   Rosette The rosette leaves are deeply lobed and may be six inches in length. Adult Spotted knapweed is a short-lived perennial one to three feet tall. The stems are moderately leaved. Flower Flowers are typically pink with spots on the flower bracts. Bloom is in early summer. Weed Infestation Originally found in Eurasia, spotted knapweed infests rangeland, pastures, roadsides, or any disturbed soils. Knapweed's release chemical substances into the soil that inhibit the growth of competing vegetation. Flower bracts Flower bracts have black tips. 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