Symphyotrichum pilosum (Willd.) G. L. Nesom
Synonym: Aster pilosus
Coefficient of Conservatism: 1
Coefficient of Wetness: 3
Wetness Index: FACU
Physiognomy: Nt P-Forb

Aster pilosus of Michigan Flora.

Two rather well-marked varieties are found in Michigan, although apparent intergrades rarely occur. 

Chiefly inland in the southern Lower Peninsula, with occasional plants in disturbed sites northward, is var. pilosum, with spreading whitish hairs on stems and leaves. This somewhat weedy variety occurs in dry to moist fields and prairies, along roadsides and shores, and even more extreme settings like pavement and concrete cracks at the edges of roads and sidewalks. It is quite late blooming and cold tolerant, and showy sometimes into early November, well deserving the common name frost aster.

Along and near the shores of the Great Lakes from Berrien and Huron Cos. north is var. pringlei (A. Gray) G. L. Nesom, with stems and leaves glabrous or nearly so. This is a calciphile, on sandy and gravelly shores and beaches, interdunal flats and swales, limestone pavements and other outcrops, rarely islightly inland. These plants, somewhat earlier blooming than var. pilosum, seem very distinctive, and warrant further study. 

The bracts and leaves around the inflorescence often have spinulose tips; the awl-like appearance of these and the tips of the phyllaries make this a reasonably easy species to recognize. Rays are normally white, but rare pink forms are known.


Alcona County
Allegan County
Alpena County
Antrim County
Arenac County
    Only on Charity Island
Barry County
Berrien County
Branch County
Calhoun County
Cass County
Charlevoix County
    Including Beaver Island
Cheboygan County
Chippewa County
    Including Drummond Island
Clare County
Clinton County
Crawford County
Delta County
Emmet County
Gogebic County
Hillsdale County
Huron County
Ingham County
Ionia County
Iosco County
Isabella County
Jackson County
Kalamazoo County
Kalkaska County
Kent County
Lake County
Lapeer County
Leelanau County
    Including Fox Islands
Lenawee County
Mackinac County
    Including Bois Blanc, Mackinac, Round Islands
Macomb County
Mason County
Mecosta County
Menominee County
Monroe County
Montcalm County
Muskegon County
Newaygo County
Oakland County
Oceana County
Ontonagon County
Ottawa County
Presque Isle County
Saginaw County
Schoolcraft County
Shiawassee 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. September 30, 2022.