What colour is the dye made from woad?
Indigo dye indigo ("Indigofera tinctoria", also known as "I. sumatrana"). A common alternative used in the relatively colder subtropical locations such as Japan's Ryukyu Islands and Taiwan is "Strobilanthes cusia". Dyer's knotweed ("Polygonum tinctorum") was the most important blue dye in East Asia until the arrival of the "Indigofera" species from the south, which yield more dye. In Central and South America, the species grown is "anil". In Europe woad containing the same dye was used for blue-dying. Several plants contain indigo, but low concentrations make them difficult to work with and the color is then more easily tainted by other dye
Natural dye it was mostly replaced by superior Indian indigo imported by the British East India Company. Woad was carried to New England in the 17th century and used extensively in America until native stands of indigo were discovered in Florida and the Carolinas. In Sumatra, indigo dye is extracted from some species of "Marsdenia". Other indigo-bearing dye plants include dyer's knotweed ("Polygonum tinctorum") from Japan and the coasts of China, and the West African shrub "Lonchocarpus cyanescens". In medieval Europe, purple, violet, murrey and similar colors were produced by dyeing wool with woad or indigo in the fleece and then piece-dyeing