Dyer's woad USDA PLANTS Symbol: ISTI
U.S. Nativity: Exotic
Habit: Forbs/Herbs
Isatis tinctoria L.

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Taxonomic Rank: Magnoliopsida: Capparales: Brassicaceae
Synonym(s): Dyers woad
Native Range: Europe (BAIL);

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 1900’s as a contaminant in alfalfa seed.

Identification, Biology, Control and Management Resources

Selected Images from Invasive.orgView All Images at Invasive.org


Steve Dewey, Utah State University, Bugwood.org
Additional Resolutions & Image Usage

Infestation;
Steve Dewey, Utah State University, Bugwood.org
Additional Resolutions & Image Usage

Infestation; 9 months after wildfire
Steve Dewey, Utah State University, Bugwood.org
Additional Resolutions & Image Usage

Root(s); Roots
Steve Dewey, Utah State University, Bugwood.org
Additional Resolutions & Image Usage

Fruit(s);
Steve Dewey, Utah State University, Bugwood.org
Additional Resolutions & Image Usage

Infestation;
Steve Dewey, Utah State University, Bugwood.org
Additional Resolutions & Image Usage

Plant(s);
Steve Dewey, Utah State University, Bugwood.org
Additional Resolutions & Image Usage

Infestation;
Steve Dewey, Utah State University, Bugwood.org
Additional Resolutions & Image Usage

Infestation;
Steve Dewey, Utah State University, Bugwood.org
Additional Resolutions & Image Usage

Plant(s); Up-rooted plant
Steve Dewey, Utah State University, Bugwood.org
Additional Resolutions & Image Usage

Plant(s); in flower
Steve Dewey, Utah State University, Bugwood.org
Additional Resolutions & Image Usage

Plant(s); in flower
Steve Dewey, Utah State University, Bugwood.org
Additional Resolutions & Image Usage

Plant(s); rosette
Steve Dewey, Utah State University, Bugwood.org
Additional Resolutions & Image Usage

Flower(s);
Steve Dewey, Utah State University, Bugwood.org
Additional Resolutions & Image Usage

Infestation;
Steve Dewey, Utah State University, Bugwood.org
Additional Resolutions & Image Usage

Control; Hand-pulling by cub scouts
Steve Dewey, Utah State University, Bugwood.org
Additional Resolutions & Image Usage

Plant(s);
Steve Dewey, Utah State University, Bugwood.org
Additional Resolutions & Image Usage

Seed(s); seeds and fruit
Steve Dewey, Utah State University, Bugwood.org
Additional Resolutions & Image Usage

Life Cycle ; Samples of reproduction, from flowers to mature fruits
Steve Dewey, Utah State University, Bugwood.org
Additional Resolutions & Image Usage

Steve Dewey, Utah State University, Bugwood.org
Additional Resolutions & Image Usage

EDDMapS Distribution:
This map is incomplete and is based only on current site and county level reports made by experts and records obtained from USDA Plants Database. For more information, visit www.eddmaps.org
 


State(s) Where Reported invasive.
Based on state level agency and organization lists of invasive plants from WeedUS database.


Invasive Listing Sources:
California Invasive Plant Council
Faith Campbell, 1998
Jil M. Swearingen, Survey of invasive plants occurring on National Park Service lands, 2000-2007
Mid-Atlantic Exotic Pest Plant Council, 2005
Pacific Northwest Exotic Pest Plant Council, 1998