Coefficient of Conservatism:
Coefficient of Wetness:
WILLOW-WEED, NODDING SMARTWEED
R. W. Smith
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.