Woad is the European plant that produces indigo pigment. The percentage of woad produced by each plant is far less than that of an indigo plant. This led to the demise of the European woad industry, which was centred in the Toulouse area here in France, in the 16th century.
Today there are signs of the production of woad reviving. For a short précis on the economic history of woad visit: woad is me.
More woad dyed crewel wool skeins coming soon!