Please try our next iteration of the Michigan Flora Online here. Beginning on February 1, 2023, will point to this new site.

The new site offers several benefits over the existing website, including real coordinate mapping, giving a clearer view of the density of documentation as well as more precision about plant distributions and their link to landforms. We will also have the ability to update species pages more regularly, both in terms of new collections and as more existing Michigan specimens are georeferenced. In addition, we have a better photo display, and offer indented keys.

Ageratina altissima (L.) R. M. King & H. Rob.
Synonym: Eupatorium rugosum
Coefficient of Conservatism: 4
Coefficient of Wetness: 3
Wetness Index: FACU
Physiognomy: Nt P-Forb

Eupatorium rugosum of Michigan Flora.

Swamps and thickets, as in ravines, floodplains, and rich hardwoods; openings and trails, cedar swamps, river banks.

Native in southern Michigan north, near the Great Lakes, to Benzie and Iosco Cos, and in the western Upper Peninsula. A 1940 collection from along a roadside in Emmet Co. was surmised to be an escaped from cultivation.

A toxic substance in this plant can cause “trembles,” a fatal disease of cattle which have browsed on it and transmittable to humans by their milk, in whom the consequent “milk sickness” caused many deaths on the 19th century frontier in this country (Duffy, 1990).


Alger County
Allegan County
Arenac County
Baraga County
Barry County
Bay County
Benzie County
Berrien County
Branch County
Calhoun County
Cass County
Delta County
Dickinson County
Eaton County
Emmet County
Genesee County
Gogebic County
Gratiot County
Hillsdale County
Houghton County
Ingham County
Iosco County
Iron County
Jackson County
Kalamazoo County
Kent County
Lake County
Lapeer County
Lenawee County
Livingston County
Macomb County
Marquette County
Mason County
Menominee County
Monroe County
Muskegon County
Newaygo County
Oakland County
Oceana County
Ontonagon County
Ottawa County
Schoolcraft County
St. Clair County
St. Joseph County
Tuscola County
Van Buren County
Washtenaw County
Wayne County


MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. February 1, 2023.