Fall boneset

Eupatorium serotinum, commonly called late-flowering boneset or late thoroughwort, is a fall-blooming herbaceous perennial in the Asteraceae family native to eastern and central North America. Plants typically reach 1 to 2 metres in height, with hairy, branching stems and alternate, ovate, serrated leaves on distinct petioles. From late summer into autumn it produces broad, flat-topped corymbs of many small, dull-white flower heads, each bearing 9 to 15 disc florets and lacking ray florets. The wind- and insect-pollinated flowers are followed by tufted achenes dispersed by wind. The species favors open sites in either dry or moist soils, including old fields, roadsides, stream banks and disturbed ground from Massachusetts west to Minnesota and Nebraska and south to Texas and Florida. Like other members of the genus it contains pyrrolizidine alkaloids and provides important late-season nectar for monarch butterflies and other pollinators.