Pycnanthemum flexuosum

Savanna mountain mint is a plant of the Southern coastal plain, at home in the wet pine savannas, flatwoods and pocosin edges that run from southeastern Virginia to northeastern Florida and west along the Gulf. A few isolated colonies also hold on in mountain bogs and granite-dome seeps in western North Carolina, which is how the plant came by the misleading trade name Appalachian mountain mint. On the coastal plain the species is a fire-adapted citizen of longleaf country, spreading slowly by rhizomes between the wiregrass and pitcher plants and flowering in the open sun after a burn. The plant has a South Carolina pedigree. Thomas Walter, a planter who botanized along the Santee River, described the species as Origanum flexuosum in his Flora Caroliniana of 1788, one of the first floras of North America written from the field. A century later the plant was moved into Pycnanthemum, from the Greek for densely flowered, a fair account of the tight heads. The epithet flexuosum means bent or zigzag, likely a nod to the stems. Mountain mints have a long history of use in the Southeast. The Cherokee are recorded applying a poultice of the leaves of this species, or of the closely related hoary mountain mint, for headache, and drinking an infusion of the leaves for fever. Across the genus, teas were taken for colds, coughs, chills and an unsettled stomach, and crushed leaves were rubbed on skin and clothing to keep off chiggers, ticks and mosquitoes. The Eclectic physicians of the nineteenth century listed mountain mint as a warming, sweat-inducing tonic. For the garden, this is one of the most useful natives a Southern gardener can grow. From early summer into fall the plant carries flat-topped clusters of tiny white to pale lavender flowers, each speckled with purple and set among white-felted, bristle-tipped bracts that make the whole head look silvered. Those heads are among the busiest in the border, visited by bumblebees, honeybees, butterflies, flies and the beneficial predatory wasps that gardeners are glad to have patrolling the vegetables. The narrow leaves smell strongly of spearmint when brushed, which is a large part of why deer and rabbits leave the plant alone. Unlike the true mints, savanna mountain mint spreads politely, building a loose colony over a few seasons rather than running across the bed. The species is a wetland plant at heart and thrives in moist or seasonally wet ground and clay, yet once established tolerates heat, humidity and dry spells with good grace. Use the silvery heads to lighten the late-summer purples and golds of a rain garden, a pond edge or a savanna-style meadow. Photos courtesy of Kristie Gianopulos