Let's complete a list of plants that we can use to dye, wool, cloth, cotton,
linen, and other textiles, the colour blue.
No need to restrict to region or climate, we're looking for a master list of natural dyes.
So far, I've played with
woad 
and
indigo 
both of them use fermentation to make a brilliant blue colour.
what other natural dyes can be used to make the colour blue?
