Formerly classified in the genus Eupatorium, which was separated into several genera after some genetic research. These dusty blue flowers are distinctive: nothing else quite like them grows around here. They have the tassely flowers of a Joe-Pye-Weed, but the powder-blue color identifies them right away. They resemble a tall version of the garden Ageratum.

Mistflower begins blooming in the middle to late summer, and can still be found blooming into fall. These plants were blooming in Bird Park in Mount Lebanon.