Infrequent to frequent in springy and wet places in woods and along streams in the southern half of the state. Formerly I did not recognize the three species of the Joe-pye-weeds and, if I had, I might have been able to extend the range of this species farther north in the state.
Similar to no. 4 [Eupatorium purpureum L.], often more robust, to 3 m; stem strongly glaucous, usually purplish throughout, hollow with a large central cavity; lvs mostly in 4's to 7's, more elliptic, generally narrowly so, with mostly finer, more rounded, blunter teeth; cor generally bright pink-purple; 2n=20. Bottomlands and moist woods; s. Me. to Io., s. to Fla. and Tex. July-Sept.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.