[8][9][10][11][12] Its preferred habitat is in moist, saturated to inundated soils growing in full sun to partial shade; such as swamp forests, marshes, streams, shorelines, and ditches.

[citation needed] Swamp smartweed is quite variable and is sometimes divided into several varieties, some of which may be better treated as species in their own right.

[2] In general, swamp smartweed is a rhizomatous perennial herb growing upright or erect and approaching a maximum height of one meter (40 inches).

The spike-like inflorescence produces many pinkish flowers each about 3 millimeters wide.

[2] Swamp smartweed is reported to be edible, as are all species in the genus Persicaria.