Asclepias tuberosa
It has many other names, including the butterfly weed, the Canada root, the chigger flower (or chiggerflower), the fluxroot, the Indian paintbrush, the Indian posy, the orange milkweed, the orange swallow-wort, the Pleurisy Root, the silky swallow-wort, the tuber root, the yellow milkweed, the white-root, and the windroot.