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   Dyer's Woad Isatis tinctoria   Rosette Leaves are blue-green with a whitish midrib. Adult Dyer's woad may be a winter annual, biennial, or a short-lived perennial. Heights of one to four feet are common. A thick tap root may penetrate to five feet deep. Flower The bright yellow flowers bloom and are highly visible in late spring. Weed Infestation Dyer's woad was introduced from Europe for production of textile dyes. It thrives in waste areas, gravel pits, road sides, pastures, field edges, and disturbed soils. Seeds Club shaped seed pods each produce a single seed. As the fruits mature they turn from green to dark brown or nearly black. Biocontrol - Rust Rust infected plants have a curley puckered look and are usually smaller than surrounding woad plants. Rust is located under the leaf surface and appears as small reddish-brown spots. 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