Joe Pye Weed (Eupatorium fistulosumis) a hardy perennial that grows 3-10 feet high and enjoys full sun and moist soil. Its hollow, purplish stem is unbranched below the flower clusters. The flower clusters are mauve or purple in color and are up to 18 inches across, although each individual flower is only about 1/3" wide. The flowers bloom from July to September and are a favorite of butterflies, bees and other pollinators. Joe Pye Weed is one of the few plants to bear the name of an American Indian. Joe Pye was an itenerant herb doctor who was active in New England in the latter part of the eighteenth century. Joe Pye is said to have specialized in treating fevers, especially those related to typhus.