joe-pye weed (jō-pī´), name for a tall North American plant (Eupatorium purpureum) of the family Asteraceae (aster family), having small, usually pinkish-purple blossoms in large terminal clusters. The name comes from that of a Native American who reputedly effected many cures with the herb. An infusion of the leaves and roots was formerly, and is sometimes yet, employed as a diuretic and an astringent, among other things. It is also called gravelroot, trumpetweed, and purple boneset or thoroughwort. Two related species, E. maculatum and verticillatum, are also called joe-pye weed. Joe-pye weed is classified in the division Magnoliophyta, class Magnoliopsida, order Asterales, family Asteraceae.