What plant yields a rich blue dye?

1 Answer
Sep 29, 2016

The leaves of several species of genus Indigofera are used to produce the blue dye - indigo.

Explanation:

Most blue colorants around the world are derived from indigo dye bearing plants Indigofera tinctoria and Indigofera suffruticosa .

Indigo is a natural and substantive dye ( direct dye ) i.e. it gives a good colour when used alone and does not need a mordant.

Indian indigo is considered most superior. Indigo dye bearing plants used in other countries are :

Polygonum tinctorium ( Japan and coastal China )
Lonchocarpus cyanscens ( W. Africa )
Marsedinia ( Sumatra )
Isatis tinctoria ( N. Europe )