Considered a noxious weed in 10 Western US states, Woad has received an undeserved bad reputation.
When properly cultivated it is a generous plant, valuable as a calcium rich fodder crop, with leaves containing, not only a natural indigo pigment, but also more anti-tumour gluco-brassican than broccoli, and seeds rich in antioxidant oils. The juice from compressed woad leaves is used in Germany as a natural antifungal treatment for wood.
It grows rapidly in warm weather and regrows swifty after being cut for dye or fodder. Its growth is so rapid that although a great amount of leaves are needed for a small amount of indigo pigment, each hectacre, in our temperate climate, cultivated in woad, can produce as much indigo as a hectacre of tropical indigo in its climate zone -- typically 20 kg. of pure indigotin per hectacre.
Why natural dyes?