Eupatorium perfoliatum L.
Boneset, Common Boneset, Thoroughwort
Eupatorium is a genus of flowering plants, part of the enormous aster family. Perfoliatum means perforated, referring to the fact that the stem appears to grow through opposing pairs of adjoined leaves. The common name, boneset, derives from the plant’s use at one time in treating dengue fever, which was also known as breakbone.
Identification: Plants reach 3' (1 m) high. The stout, very hairy stem branches at the top to support the flowers. Leaves are up to 8" (20 cm) long, long and narrow, with pointed ends and fine serrations. Prominent veins produce a rough upper surface and a hairy, somewhat sticky lower surface. Opposite leaf pairs are joined around the stem (“connate”), so that the stem appears to be growing through them, a major identifying trait. Small, dull white (sometimes pinkish) flowers emerge in flat-topped or slightly dome-shaped clusters at the top of the stem, which branches to support multiple clusters. Individual flowers are about ⅛" (3 mm) in diameter. The flowers lack petals (“rays”) and look like tiny shaving brushes.
Medical: Boneset has a long and often dubious history of medicinal use. Its opposite pairs of joined leaves were once thought to signify the power to heal broken bones. It was used to treat dengue fever. It was also used as a stimulant, and a laxative. Leaves brewed into a tea have been used to reduce fever, its primary use. There is no evidence to support any of these uses, and some evidence of mild toxicity—plants “should not be ingested.”
Some similar species:
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Ageratina altissima ‘Chocolate’
|Plant||Plants reach 3' (1 m) high.||Plants are 3-5' (91-152 cm) high, and up to 3' (91 cm) around, with single or multiple stems.|
|Flowers||Small, dull white (sometimes pinkish) flowers are flat-topped or slightly dome-shaped clusters. Individual flowers are about ⅛" (3 mm) in diameter. The flowers lack petals (“rays”) and look like tiny shaving brushes.||Flowerheads are somewhat dome-shaped clusters, each with 10-30 white brushlike flowers with no petals. Each flower is about ⅛" (4 mm) around.|
|Leaves||Opposite leaf pairs are joined around the stem, so that the stem appears to be growing through them. Leaves are up to 8" (20 cm) long, long and narrow, with pointed ends and fine serrations. Prominent veins produce a rough upper surface and a hairy, somewhat sticky lower surface.||Leaves are 2-5" (5-12 cm) long, lance-shaped, and tapering at both ends; lower leaves are broader, more heart-shaped. Each leaf has three prominent veins and serrated edges. Leaf stems (petioles) are ½-1½" (1.3-3.8 cm) long. Leaves are darker in the 'Chocolate' cultivar.|
|Stem||The stout, very hairy stem branches at the top to support the flowers.|
USDA Zones: 3-10
USDA Zones: 3-8
USDA Zones: 4a-8b
|Habitats||Damp fields, low meadows.|
Eupatorium perfoliatum on Missouriplants.com
Eupatorium perfoliatum at the Lady Bird Johnson Wildflower Center
Eupatorium perfoliatum on Botanical.com
Eupatorium perfoliatum at Illinois Wildflowers
Eupatorium perfoliatum on eFloras
Eupatorium perfoliatum on the Connecticut Botanical Society's Connecticut wildflowers site
Eupatorium perfoliatum at the Missouri Botanical Garden
Eupatorium perfoliatum on Plants for a Future, a resource and information centre for edible and otherwise useful plants
Eupatorium perfoliatum on eFloras
Newcomb, Lawrence, Morrison, Gordon (Illus.), Newcomb’s Wildflower Guide, Little, Brown and Company, 1977, p. 434
Eupatorium perfoliatum description by Thomas H. Kent, last updated 2 Jan 2019.
Range: Zones 3-8: