Plants used for medicine need to be memorable, which often meant having showy flowers. To paraphrase Dr. Moerman, if you find something that seems to work, you need to be able to find it again. It quickly becomes more complicated as you need to be able to teach it to your village and tribe. In those times most people didn't live past thirty, so the window of opportunity for someone to learn, use and communicate something was relatively short. And just think of how much of your time was taken up by time with a teenage brain! Or younger. The common name apparently comes from Jopi (anglicized to Joe Pye), an Indian healer encountered by early European alien invaders. Sweet joe-pye-weed has 25 citations in the Native American Ethnobotany Database. It's a very memorable plant, standing head high, with an inflorescence as much as a foot across. borders and woods, often moderately wet, in AL, AR, CT, DE, FL, GA, IA, IL, IN, KS, KY, LA, MA, MD, ME, MI, MN, MO, MS, NC, NE, NH, NJ, NY, OH, OK, PA, RI, SC, TN, VA, VT, WI, WV, and ON. Lenawee Co MI, 7/24/11.