I planted Spiderwort fall 2009 and all last summer, I was rewarded with pretty blue flowers on a daily basis. They would bloom in the morning and be done by afternoon.
I found this website when I was looking up more information after I discovered they are also edible through a friend's posting on facebook:
I'm looking forward to trying out these for eating and dying!
Dye recipe for future reference:
8 cups of water
8 cups of blue flowers, no green
Combine flowers with water and bring to boil, then set away from heat and let set overnight.
Come morning, strain the plant out, and save the blue water.
Dissolve 1 tablespoon alum with 1 teaspoon cream of tarter in a small amount of hot water, and stir into dye. Use a long wooden spoon and be sure it dissolves good.
Add white fabric, soak over nite or till it is as dark as you want.
The alum sets the dye in the fabric and the cream of tarter makes the dye a brighter color and softens the fabric.