Veronicastrum virginicum

Veronicastrum virginicum (Culver's root, Culver's-root, Culverphysic, Culver's physic, Bowman's root, black root; syn. Leptandra virginica (L.) Nutt., Veronica virginica L.) is a wildflower native to the United States from southern Maine to northwest Florida to northern Louisiana up through Minnesota and going over the Canadian border a little bit; good for USDA zones of 3 to 8.