RECOMMENDED NATURAL DYE BOOKS: Any that you can get your hands on, as they quickly go in and out of print. It seems there just isn't a huge market for them, at least not enough for large printings or to keep them in print for any length of time. Just be sure that you find one that discusses proper safety concerns and fully explains mordants and how to safely handle them! That said, here is a list of my own dye books, generally listed from most to least referred to. There are many others out there, as well.
Wild Colors by Jenny Dean and Karen Diadick Casselman. I'm really hoping this one comes up for a reprinting. It's both modern, asthetically beautiful, inspiring, and informative.
2/17/2009: Jenny Dean is now online at her blog, too.
9/1/2020: LOOK! It is being reprinted! The revised & updated edition will be released on November 16, 2010.
North American Dye Plants, by Anne Bliss (possibly slanted towards the mountain west, but also crosses into other regions)
Natural Dyes from Northwest Plants, by Judy Green. (Pacific Northwest US)
Craft of the Dyer, by Karen Leigh Casselman (ANYTHING by her is wonderful, informative, and inspiring, in my opinion. How I'd love to meet her!)
Nature's Colors: Dyes from Plants, by Ida Grae, (Northern California)
A Dyer's Garden, by Rita Buchanan
Dyes from Nature, published by the Brooklyn Botanical Garden Record, 1990.
Dye Plants & Dyeing, published by the Brooklyn Botanical Garden Record, several reprintings. On Amazon there are several editions and many listings for this booklet, as well as one for another book that goes by the same name.
A Handbook of Dyes from Natural Materials, by Anne Bliss. A compilation of dye "recipes" from many dyers.
Dyeing the Natural Way, by Fances E. Mustard
Natural Dyes and Home Dyeing, by Rita J. Adrosko
The Dye-Pot, by Mary Frances Davidson. My copy is signed by the author with the words, "Live to dye". Also, the book is dedicated, "To Mother, who never fussed if the sink was stained."
Nature's Dyepot, A Resource Guide for Spinners, Weavers & Dyers, by Bobbi A. McRae.
Sometimes, as well, I've run across articles on natural dyeing in old issues of magazines, including: Country Living, Country Living Gardener, Threads (before it became a strictly sewing related mag), Shuttle Spindle & Dyepot, Heddle, Handwoven, National Geographic, Spin-Off, Piecework, even Martha Stewart Living.