Persicaria lapathifolia (L.) Delabare
Synonym: Polygonum lapathifolium
Coefficient of Conservatism: 0
Coefficient of Wetness: -3
Wetness Index: FACW
Physiognomy: Nt A-Forb

Polygonum lapathifolium of Michigan Flora.

Like P. pensylvanica, a species of moist shores, river margins, marshes, mucky hollows, and moist (rarely dryish) disturbed ground. Some of our populations may be introduced from Europe; the weedy habit has obscured any distinction between native and introduced sources.

Variable in pubescence, color, and stature. Some plants (especially when young) have leaves tomentose beneath. Plants range from several cm tall to as high as 2 m, and have very conspicuously swollen nodes and typically nodding inflorescences of pink to white flowers. Another annual often locally abundant and producing copious achenes. The smartweeds bloom late in the summer and into fall, and are readily laid low by the first frost.


Alcona County
Alger County
Allegan County
Alpena County
Arenac County
Baraga County
Barry County
Bay County
Benzie County
Berrien County
Calhoun 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
Gladwin County
Gogebic County
Gratiot County
Hillsdale County
Houghton County
Huron County
Ingham County
Iron County
Isabella County
Jackson County
Kalamazoo County
Kalkaska County
Kent County
Keweenaw County
    Including Isle Royale
Lapeer County
Leelanau County
    Including Fox Islands
Lenawee 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
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. June 29, 2022.