Indigo

Indigo is a small shrub of the bean family, growing to about one or two metres, with pinnate leaves of small bluish-green leaflets, spikes of pink to violet pea-like flowers and slender pods. It is grown across tropical India and was one of the world's main sources of natural blue dye.

The leaf is used. Ayurveda knows it as Nili and traditionally uses it in hair oils such as Nilibhringadi and in natural hair colour, where powdered indigo is applied after henna to give dark tones.