Appearance
Isatis tinctoria is a biennial member of the mustard family that can grow from 1-4 ft. (0.3-1.2 m) tall.

Foliage
First years growth is represented by a rosette of hairy, bluish-green leaves 1.5-7 in. (3.7-18 cm) long. Stem leaves are lance-shaped and alternate with a cream-colored mid-rib.

Flowers
Flat-topped yellow flowers with four spoon-shaped petals appear in small clusters at the top of the stems. Flowering occurs in spring to late summer.

Fruit
Seed pods are black or purplish, flattened, 0.4 in. (0.9 cm) long, 0.25 in. (0.6 cm) wide and hang from short stalks at the ends of the stems.

Ecological Threat
Isatis tinctoria occurs in areas with poor, dry soils such as roadsides, rangelands, and open forests. Isatis tinctoria is native to central Asia and northern Russia and was introduced to North America in the early 1900s as a contaminant in alfalfa seed.

Resources

• Weed of the Week - USDA Forest Service
• Weed Field Guide - USDA Forest Service

Selected Images

Maps

Invasive Listing Sources

• Alberta Weed Control Act
• Arizona Noxious Weeds
• California Invasive Plant Council
• California Noxious Weeds
• Colorado Noxious Weeds
• Idaho Noxious Weeds
• Jil M. Swearingen, Survey of invasive plants occurring on National Park Service lands, 2000-2007
• Montana Noxious Weeds
• National Park Service, Mid-Atlantic Exotic Plant Management Team Invasive Plant List
• Nevada EDRR
• Nevada Noxious Weeds
• New Mexico Noxious Weeds
• Oregon Noxious Weeds
• Pacific Northwest Exotic Pest Plant Council, 1998
• Utah Noxious Weeds - Control
• Washington Noxious Weeds
• WeedUS - Database of Plants Invading Natural Areas in the United States
• Wyoming Noxious Weeds

References