Perennials, aromatic. Stems prostrate, 15–30 cm, hairy. Leaves hairy; blade base broadly cuneate, margins entire, apex obtuse. Pedicels 5–15 mm; bracteoles present. Flowers: sepals 5, ovate, calyx bilaterally symmetric; corolla violet-blue with violet-blue throat, 10–13 mm, lobes 4; stamens 2–4, didynamous.
Phenology: Flowering Jun–Nov.
Habitat: Marshes, swamps, margins of streams, pastures.
Elevation: 0–300 m.
Ala., Fla., Ga., La., Md., Miss., N.C., S.C., Tex., Va.
Bacopa caroliniana is used in aquascaping in freshwater aquariums. The species can be propagated vegetatively through cuttings. The leaves of B. caroliniana are lemon scented when crushed.