Dyer’s Woad

Isatis tinctoria

Plant Description

A winter annual, biennial, or short-lived perennial mustard with a 3 to 5 foot deep taproot. Basal rosette with bluish green leaves; stem leaves are lance shaped, alternate, and not stalked; all leaves have a cream-colored mid-vein. Small yellow flowers with 4 sepals, 4 petals, and 6 stamens.

Plant Details

Life Forms
Habitats
ODA Listing
Soil and Moisture Conditions
Suggested Actions
Shade Preference
Mature Height 1-4'
Distribution According to ODA, There are multiple historic sites scattered throughout Oregon that have been eradicated. Currently, Klamath and Lake Counties have the most infested acres.
Control Hand pulling and digging after plant bolts but before seeds are produced, are recommended control options for difficult terrain. Active mowing will control orchard populations. It can be cultivated twice a year for control- once before seed prodcution and a second time in late fall.
Reproduction and Spread Reproduces by seed; each plant can produce 350-500 seeds, some produce up to 10,000 seeds.
Introduced Native to Russia, introduced to Utah from Ireland in 1910.
Look Alikes other mustards, especially yellow or common mustard
Impact This allelopathic plant forms dense clolines in rangelands, damages crops, and destroys wildlife habitats.
More Info
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