Dyer’s woad (Isatis tinctoria) is a problematic, invasive weed in the intermountain west, including far northern California. It grows in both disturbed
and undisturbed sites and can be commonly found along roadsides, fencerows, and ditch banks, as well
as in pastures, rangeland, and natural
areas. It is sometimes also found growing in field crops.
Until a couple of decades ago, it was primarily confined to Scott Valley in Siskiyou County, but it has subsequently spilled over into Shasta Valley and continues to
spread throughout Siskiyou County and into Modoc, Shasta, and other northern California counties.
Dyers Woad is is a ‘B’ listed noxious weed in California.
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