Eupatorium (yew-pat-toh-ree-um) Throughwort, Joe Pye Weed. Asteraceae Family. Perennial, some tropical, some native to North America, have clusters of blue, purple or white flowers that bloom in July, August and September.
This perennial plant has a longstanding place of honor in herbal medicine, and is equally at home blooming in a cultivated border or a natural wildflower setting. According to Pliny the Elder, Roman author, Mithridates VI Eupator was the first to use a plant of this genus for liver complaints. Joe-pye weed is native to the U.S., and this common name refers to an American Indian who used the plant to cure an early settler of typhus. Another common name is boneset, which refers to the plant's diaphoretic properties that aided in the treatment of "break-bone" (Dengue) fever.
Eupatorium grows effortlessly in average, medium moisture soils. In full sun to part shade, Eupatorium prefers moist, fertile, humus soil which does not dry out. Plants should be cut to the ground in late winter.