Schwalbea americana occurs in acidic, sandy or peaty soils in open pine flatwoods, longleaf pine/oak sandhills, streamhead pocosins, pitch pine lowland forests, seepage bogs, palustrine pine savannahs, in ecotonal areas between peaty wetlands and xeric sandy soils (NatureServe 2001). Historically, the species is known from inland sandplains in Albany, New York and central Massachusetts. The species is regarded as a facultative wetland plant (USDA Plants National Database 2001); individual plants sometimes occur in drier upland communities, but rarely inhabit inundated wetlands (Rawinski and Cassin 1986). Associated plant communities are typically species-rich, and dominated by grasses and sedges. Plant genera reported to occur with Schwalbea americana in the Southeast include grass species of Andropogon, Aristida, Panicum, and Paspalum; sedge species of Carex, Dichromena, Fimbristylis, Rhynchospora, Scleria; monocot species of Aletris, Calopogon, Eriocaulon, Juncus, Lachnocaulon, Xyris; and dicot species of Asclepias, Buchnera, Erigeron, Eryngium, Helenium, Heterotheca, Orbexilum, Phlox, and Polygala. In wetter habitats, species of Cliftonia, Gaylussacia, Ilex, Lyonia, Leucothoe, Myrica, and Vaccinium occur as associates (Fernald 1939, Kral 1983, NatureServe 2001).