In fertile soils, rhizomes can grow more than 50 mm per day. Rhizome fragments can develop new shoots. The following characteristics apply except where noted. Glandular disc orange-red. Veins of outer lobes forked and curved outwards at tips.
Sepals dull deep pink to white .
Glandular disc yellow-green. Achenes shiny, brown to black. Pale smartweed , ladysthumb , and the foliage of swamp smartweed are killed by the first frost. Foliage turns brown to reddish and does not persist through the cold season. Rhizomes of swamp smartweed survive cold winter climates.