Hypericum perforatum. This is a perennial plant forming a woody low shrub about 2 feet high covered in little yellow starry flowers all summer. It is also used as a herbal remedy. Fresh flowers give a good yellow/green dye, continuing to simmer the dye bath will give reddish-browns, golds and tans - several different colours available from the same batch of dye! The full method is  described in Rita Buchanan's book 'A Dyer's Garden' -see our books section.

Saint John's Wort can be used to give yellow, green, reddish brown and tan dyes

part to use for dyeing; fresh flower heads 

Mordant; Alum