Physostegia purpurea is a southeastern native with a narrow natural range, found in North Carolina along the coastal plain in wet savannas, swamp margins, and ditches near former pinelands. It grows 2 to 3.5 feet in moist, well-drained sandy soils without humus, a somewhat unusual combination that reflects its specialized origin. The purple flowers bloom from May through August, providing a long season of color in habitats where sustained flowering is not always easy to achieve.

In cultivation, it belongs in full sun with reliably moist conditions — bogs, rain garden edges, or consistently wet low spots where other ornamentals falter. It attracts bees and hummingbirds across its long bloom window. Hardy from zone 8 to 11, it is best suited to mild coastal climates, and it is not salt tolerant, so keep it back from the immediate shoreline.