Achillea millefolium L.
Common Name: YARROW, MILFOIL
Coefficient of Conservatism: 1
Coefficient of Wetness: 3
Wetness Index: FACU
Physiognomy: Nt P-Forb

Almost everywhere, especially dry roadsides, railroads, fields, and disturbed places; rock shores and cliffs, dry savannas, grasslands; less often in moist ground (sometimes peaty), shores, river banks, and meadows.

Although weedy in habit, most of our plants are presumably native. Achillea millefolium, as treated here and in most other recent works, is a polyploid complex of native and introduced plants that hybridize and intergrade with one another. There is an apparent gradient from north to south in decreasing incidence of dark-bordered phyllaries (with various shades of intermediate and light brown also occurring). Plants with rays light to deep pink are rather frequently found. Some of the deepest magenta shade are doubtless cultivars of the Eurasian species and some may well be (as documented in Quebec) pentaploid hybrids. Native tetraploids tend to have a lighter rosy shade.

Yarrow has a strong aroma, especially when bruised, though less intense than that of Tanacetum.

Locations

Alcona County
Alger County
Allegan County
Alpena County
Antrim County
Arenac County
Baraga County
Barry County
Bay County
Benzie 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
Dickinson County
Eaton County
Emmet County
Genesee County
Gladwin County
Gogebic County
Grand Traverse County
Gratiot County
Hillsdale County
Houghton County
Huron County
Ingham County
Ionia County
Iosco County
Iron County
Isabella County
Jackson County
Kalamazoo County
Kalkaska County
Kent County
Keweenaw County
    Including Isle Royale
Lake County
Lapeer County
Leelanau County
    Including Fox Islands
    Including Manitou Islands
Lenawee County
Livingston County
Luce County
Mackinac County
    Including Bois Blanc, Mackinac, Round Islands
Macomb County
Manistee County
Marquette County
Mason County
Mecosta County
Menominee County
Midland County
Monroe County
Montcalm County
Montmorency County
Muskegon County
Newaygo County
Oakland County
Oceana County
Ogemaw County
Ontonagon County
Oscoda County
Otsego County
Ottawa County
Presque Isle County
Roscommon County
Saginaw County
Sanilac County
Schoolcraft County
Shiawassee County
St. Clair County
St. Joseph County
Tuscola County
Van Buren County
Washtenaw County
Wayne County

Citation:

MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. December 17, 2017. http://www.michiganflora.net/species.aspx?id=207.