thoroughwort

Thoroughwort is a common name for several species of flowering plants in the Asteraceae family, most notably the North American boneset (formerly Eupatorium perfoliatum). The name is also applied to other related species in Eupatorium and in related genera, now mainly placed in Eutrochium or Eupatorium depending on the classification system.

Description: Thoroughworts are herbaceous perennials with opposite leaves; in many species leaves may be perfoliate, appearing to encircle the stem. They produce clusters of small white flowers at the ends of flowering stalks from midsummer to early autumn.

Distribution and habitat: Native to eastern North America, thoroughwort species commonly inhabit wetlands, swamps, damp meadows, stream banks, and riparian areas. They prefer moist soils and full sun to partial shade.

Taxonomy: Because of modern taxonomic revisions, several species formerly placed in Eupatorium are now in other genera such as Eutrochium. The term thoroughwort remains a common name for these plants and is especially associated with boneset.

Uses and ecology: Historically, some thoroughworts were used in herbal medicine for fevers and colds; however, scientific evidence is limited and use should be cautious. Ecologically, thoroughworts provide nectar to pollinators, supporting bees and butterflies late in the season.