Helianthus giganteus Linnaeus. Tuberous Sunflower, Swamp Sunflower. Phen: Late Jul-Oct. Hab: Roadsides, woodland edges, bog edges, moist thickets, ditches. Dist: NB and ME west to MN, south to n. SC, n. GA, e. and c. TN, c. KY, n. IN, n. IL, and WI.
Origin/Endemic status: Native
Syn: = C, F, FNA21, G, GW2, Il, K1, K3, K4, Mi, NE, NY, Oh3, Pa, RAB, S, SE1, Tn, Va, W, WV; > Helianthus alienus E.Watson – S; > Helianthus giganteus L. – S; > Helianthus validus E.Watson – S