"We always think of nettle as this awful thing that stings and hurts," said Sonia Uyterhoeven, gardener for public education at the New York Botanical Garden. "But if you chop it up and soak it, you get lovely yellows and greens. Just make sure to harvest it using thick gloves."
Even succulent plants can be used to make dyes, said Duerr, who recommended aloe for pinks and yellows and jade plants for purples and black. Wild fennel, abundant in northern California, yields fluorescent yellows "so bright they hurt your eyes" if harvested while in bloom.
"It's like making tea. You boil the plant and then simmer," she said. And like cooking, the results depend as much on the chef as on the recipe. "The beauty of it is that you can take something from the back of your closet and give it new life using just the waste from your dinner."
Any plants containing sufficient tannins can be used to achieve colorfast fabrics without additives, known as mordants. But there are also natural mordants, such as rhubarb, sumac, pomegranate rinds, lemon juice or vinegar, according to Uyterhoeven. With a mordant, sumac fruit yields red pigment and indigo yields its classic shades of blue. Cream of tartar can be used to brighten colors, and salt to intensify them.(RJ1) (RJ1)
"Just about anything you feel comfortable around, like blackberries or elderberries, should be fine, but there are some plants that should be avoided," she warned.
Lily of the Valley is toxic and could harm the water supply if you dump it down the drain, she said, and although Native Americans traditionally used bloodroot for natural dyes, "it's not a large plant, so if you start using it for dye you're depleting the population."
The beautiful purple berries on pokeweed plants, although tempting, are poisonous and should also be avoided, Uyterhoeven said.