Eupatorium hyssopifolium


Eupatorium hyssopifolium, also known as hyssopleaf thoroughwort, is a fall-blooming herbaceous plant native to North America. Like other members of the genus Eupatorium it has inflorescences containing a large number of very small flower heads, each with 5 white disc florets but no ray florets. At 0.5 to one meter tall, it is towards the shorter end of the range of heights found in Eupatorium species.
Plants which are classified as E. hyssopifolium can be either diploid or polyploid, and some of them seem to have been the result of past hybridizations with Eupatorium serotinum. Hybrids with E. album and E. linearifolium also seem to exist. The hybrid E. torreyanum is similar to E. hyssopifolium but is a hybrid of E. serotinum and Eupatorium mohrii.
;Varieties
  • Eupatorium hyssopifolium var. hyssopifolium - leaves 2–5 mm wide
  • Eupatorium hyssopifolium var. laciniatum A.Gray - leaves 5–15 mm wide

Distribution and habitat

Eupatorium hyssopifolium is found in much of the eastern and south-central United States, from Massachusetts west to Wisconsin, and as far south as Texas and Florida. Listed as endangered in the state of Ohio. It grows in moist soils and can be found in woodlands and oak savannas, pastures, fields, roadsides, and disturbed areas, over both acidic and calcareous substrates.

Ecology

Eupatorium hyssopifolium increases in abundance with fire disturbance, and is most commonly found in habitats with high fire return intervals.

Uses

Eupatorium hyssopifolium can be used medicinally. It can also be planted near crops to attract beneficial insects.