So I played around with the bloodroot, and although I got a lovely yellow, I never achieved the red I anticipated and since there are so many abundant sources of yellow from natural dyes that don't require killing the plant, I probably will just enjoy bloodroot for it's flower in the future.
As several sources I read suggested soaking the bloodroot in alcohol rather than water, a common enough extraction method, I did so. As you can see from above, the roots look like carrots! Then I diced them and did a further smashing as best I could in my mortar & pestle...they were rather resistant to this, but I tried. Then I soaked the first batch (and I admit I was stingy with the quantity of root I used at first because I was experimenting)in an alcohol/h2o mix for a couple of hours until I saw a lovely orange fluid. Then I heated it up and threw in a sample skein. The color was so faint, even after additional alum was added and it cooked for an hour, that I decided I needed to up my starting dye material.
So I chopped up the all the remaining roots...probably about 20 more, extracted them for a couple of hours in straight alcohol, added the extract from them to the dye pot and threw in more yarn. This time I added a singles cormo/mohair (1 of the lovely yarns for the Vermont Yarn Club), a tightly plied merino (Gems by Louet), and a plied border leciester (another lovely Vermont Yarn Club sample). They all came out a lovely yellow, but never red, even after playing with the pH to shift the color. The only thing I thought to try, but found I had none in stock, was to add a pinch of tin to "bloom" the color (an afterbath of tin often "pops" the color in a natural dyebath).
Anyway, it was interesting, but since the flower is so pretty itself (see above) I won't be tempted to try it again unless someone shares with me the secret to getting the deep red....anyone have any ideas?