Northern Prairie Wildlife Research Center
SMARTWEED FAMILY (Polygonaceae)
IND. STATUS: FACW+
FIELD CHARACTERISTICS: An annual herb growing to a height of 2 m. (but sometimes growing along the ground). The upper parts of the stem have minute, sticky glands. The leaves are lanceolate. The inflorescence is cylindric and 1-1.5 cm. wide. Flowers are white to pink to rose and 3-4 mm. long. The swollen nodes, characteristic of smartweeds, lack bristles. Fruit is a shiny nutlet 2.2-3.5 mm. broad. In flower during July to September.
ECOLOGICAL NOTES: Pinkweed is found in shallow marshes and disturbed areas, especially on recently exposed mudflats, cultivated land, and dredged material disposal sites. There are about 30 species of smartweeds (Polygonum spp.) in Minnesota and Wisconsin.
The nutlets of pinkweed, and smartweeds (Polygonum spp.) in general, are an important waterfowl food. They are also of significant food value to many songbirds.
SOURCE: Fernald (1970); Gleason and Cronquist (1991); Martin et al. (1951); and Voss (1985).