posted 1 week ago
Will depend on the climate. Here are a few I saw walking around my garden.
Yellow
Broom flowers, weld, dandelion flowers, st johns wart, oregon grape
Red
Madder, some temporary reds from berries. Woad seeds give pink. Arbutus bark is a great one for linen and sticks well even without mordant.
Blue
Woad and indigo are the main ones
Green
Rhubarb leaves (no mordant needed, but helpful), nettles, carrot tops although this can sometimes give yellow instead.
With cotton, "dying" it with some sort of tannin like from oak leaves helps to make the mordant stick. Three baths for longer lasting colour: Tannen, mordent, dye