Information on each plant is organized in a useable structure. I have attempted to make the most sought after information readily available, having been frustrated with finding this myself. In recipes, all additives and dyes are added to the dyepot based on WOF (Weight of fabric) of 1lb of fiber, to make calculations easier. Please adjust as you need.
This is by no means an exhaustive list of dyes that can be obtained from plants. Just for fun, see the list sorted by color, by plant family or by plant part used.
Cutch
Fustic
Madder
Myrobalan
Onion skins
Persimmon
Pomegranate
Redwood
Walnut
Weld