Slender Mountain Mint (Pycnanthemum tenuifolium)
Slender mountain mint, native to eastern and central United States, offers exceptional ecological benefits, especially in prairie restorations and pollinator gardens. Its dense clusters of nectar-rich flowers support a wide diversity of native bees, butterflies, and beneficial flies, making it a very beneficial species for midsummer to fall forage. It spreads modestly by rhizomes, while its aromatic foliage deters browsing by deer and rabbits—allowing it to persist in challenging sites.
Slender mountain mint typically grows to a height of 2 to 3 feet. Its small, white flowers, often dotted with purple spots, are about 1/4 inch long and bloom in dense, terminal clusters. The leaves are very narrow and almost needle-like, up to 3 inches long and about 1/4 inch wide. They are opposite, linear, and hairless, with a prominent central vein and smooth margins. Slender mountain mint is adaptable and occurs in dry, open rocky woods, dry prairies, fields, roadsides, and the drier margins of stream corridors, as well as seasonally moist thickets. It prefers full sun to part shade and grows well in dry to medium soils.
Sources:
Flora of North America — Pycnanthemum tenuifolium
USDA Plants Database — Pycnanthemum tenuifolium profile
Illinois Wildflowers — Slender Mountain Mint
Lady Bird Johnson Wildflower Center — Pycnanthemum tenuifolium
Missouri Botanical Garden — Pycnanthemum tenuifolium plant details
(SF)