Superb natural blue dyes can be obtained from several different indigo-producing plants. Most of the blue dye plants are not closely related and come from different dye plant families.
Woad, which is related to cabbage, is the principal blue dye plant in Europe.
True indigo, related to beans, has been used for centuries in India and, indeed, the word indigo originally meant a dye from India.
In Asia most of the indigo dye comes from Japanese Indigo, which is related to rhubarb and dock. The Americas and Africa have their own species of indigo dye plants.
The logwood tree from the tropics and true alkanet from semi-desert areas also produce important purple and blue natural dyes.
