Eupatorium semiserratum

small-flower thoroughwort, smallflower thoroughwort, smallflower eupatorium
Family

Asteraceae

Leaf Arrangement

opposite, whorled

Leaf Attachment

petiolate, sessile

Leaf Margin

crenate, serrate

Leaf Type

simple

Leaf Shape

elliptic, lanceolate, oblanceolate

Growth Form

forb

Flower Color

white

Flower Month

July - October

Height (meters)

0.3 - 1.8

Milky Sap

No

Armed/Unarmed

Unarmed

Origin

native

Lifespan

perennial

Growing Season

Warm season


Wetland Class

FACW

Prairie Coefficient of Conservatism

5

Field Characters

Similar to E. serotinum but has a petiole that is less than 2 mm long or absent and its leaf blade margins are toothed only on the upper half while E. semiserratum has a petiole that is more than 2 mm long and its leaf blades are toothed below the middle. Also similar to Ageratina altissima which occurs on similar sites but has shorter petioles (E. serotinum has petioles up to 1 inch long). Opposite leaves, 5 teeth on each side of leaf. Deep purple stem, non-woody.

Animal Use

The seeds of several Eupatoriums are eaten by birds.

Natural History

Found frequently in sandy soils throughout Louisiana, east and southeast Texas (south to Aransas County). Occurs throughout the Southeastern United States. The species in this genus had many medicinal uses by early pioneers. Their leaves were used as a poultice under splints to heal broken bones, which explains the origin of its common name, "boneset."

Habitat

Savannas, pine barrens, bogs, swamp forests, low woods, and clearings.