Natural Dyes and awareness of where textiles come from and the impact of its manufacture is gaining popularity! Read this NYTimes article Colors of the Caldron about natural dye gardens cropping up in NYC.
Our guild had a natural dye workshop last year were we got to dye our roving and handspun fibers. There was walnut, onion skin, woad, golden rod, and indigo among others.
Many natural dye plants grow wild in our area and there a lot of resources online to help you start thinking about those dye gardens.