Bloodroot, red osier dogwood bark, wild plum bark, and alder bark are some of the plants that were traditionally used to make a red dye for fabrics and porcupine quills. One formula I've seen involves boiling about a handful of each of these together in about a quart of water, then boiling the article to be dyed in with it awhile, then let it sit for a few hours. It's supposed to produce a pretty vivid red color.