Persicaria tinctoria

Persicaria tinctoria (Ait.) H.Gross is a dye plant.

Colors
It yields a blue colour.

Parts used
Colorants are extracted from the leaves and stems of the plant.

Methods
A vat is needed to achieve the blue colour with this plant.

Synonyms
Polygonum tinctorium Ait.

In japanese the colour made by this plant is called 藍 [ai], it's also known as 蓼蓝 [Liǎo lán] in Mandarin and Bai ya in Dong communities.