A friend posted this on FB.
http://www.gizmag.com/dyes-from-agricultural-waste-inti/17598/ (http://www.gizmag.com/dyes-from-agricultural-waste-inti/17598/)
I know that walnuts are used in dyes too.
Meh.
The big hurdle here is that they aren't light-fast, those natural dyes. Not without a mordant that eventually destroys the fabric (or other cellulosic substrate).
That's not news, and people have been trying to solve that problem for several centuries. I'm not too worried.