This book has a wealth of gorgeous photography and tons of information on coloring with botanicals. If I stopped there, it would get 5 stars.
The main drawback is that the book's organization is awkward, requiring much study and flipping around to figure out how best to use the botanicals at your disposal. To be fair, much of the information is complicated, making it hard to organize; and there is a good index to help you find that stray sentence you need. If you are willing to plow through and experiment, Eco Colour is a great foundation and inspiration. There are actually a couple "recipes" for quick and easy eco-prints, but patience is still required (the author advises waiting a week to open that lovely bundle of now-rosy silk I tinted with red onion skins!) When you try the flower pounding, please do take the author's advice to make a trial, even if you have limited plant material to work with! :-)
One thing the reader should not miss is that the author admitted drawing during chemistry class! She mentions early in the book the reliable color results that can be obtained using certain chemicals, without the specific caution that these are quite toxic, cautions she does, however, repeat concerning plants that are poisonous, etc. (Please be sure to look up an MSDS if you are tempted to order any chrome salts, etc.)
One of the most helpful things to me was the extensive information on the friendlier mordants, which ones are useful on which types of fiber, and how various ones may affect the final colors you will achieve. We benefit also from little tricks she has learned, such as freezing certain flowers or berries to extract the most color. (Spent blossoms are in the freezer now and will be my next project.) I was fascinated with her ingenuity in figuring out how to dye "on the road" with botanicals encountered while traveling.
While chemical dyes (such as Procion MX) are safe, much easier, more predictable, wash- and light-fast, there is a definite allure to trying to capture the beauty of the plants around us to color our clothing and other fabrics, even if it is fleeting. Eco Colour is a great book for your adventure.