Pycnanthemum flexuosum aka Appalachian Mountainmint

Pycnanthemum flexuosum is in the mint family and lives for years. Its common names include Appalachian mountain mint and savannah mountain mint. It comes from the southeastern United States. Its range runs from Virginia south to Florida, west to Mississippi. It grows in meadows, pastures, open woods, and along roads. In North Carolina, it grows near the coast and in the Piedmont.

This plant grows upright in clumps. It spreads at a slow pace through rhizomes, or underground stems. Garden plants reach 2–3 feet (0.6–0.9 metres) tall. They spread 1–3 feet (0.3–0.9 metres) wide. RHS gives an upper size of 3.3 feet (1 metre) each way. The green stems branch and are square in cross-section. Thick green leaves grow in pairs, one on each side. Some leaves are oval; others are narrow and lance-like. They smell of spearmint and have teeth along their edges. These edges may turn red in autumn before the leaves fall.

Small, tube-shaped flowers form round groups at the stem tips. The petals range from white to pale lavender, with purple spots. Bloom starts in late summer and lasts about two months. Pale sepals, the outer flower parts, stay when the petals fade. They give the heads a fuzzy look. Dry seed pods, or capsules, and seedheads add interest through winter. Bees, butterflies, moths, and wasps visit the blooms. Swallowtails feed on the nectar. Gray hairstreak butterflies and wavy-lined emerald moths use it as a host.

Grow it in sun or part shade in soil that drains well. It prefers rich, moist loam but grows in many soil types. Acid, neutral, and alkaline soils all suit it. Once plants take root, they cope with drier ground. It grows in USDA zones 5–8. RHS gives it a hardiness rating of H7. It needs little care and has no serious reported problems. RHS lists few pest or disease concerns. Deer and rabbits tend to leave it alone. Grow new plants from seed or split clumps in spring. Leave seedheads for winter, then cut old stems in early spring.

Use this mint in borders, meadows, wildlife gardens, or woodland edges. It also suits rain gardens and ground near ponds or streams. Plants on slopes can help stop soil loss through erosion. Past herbal uses include treating stomach trouble, fevers, and headaches. These reports do not prove that such use is safe or helps. One food-use report does not name the part or how to prepare it. PFAF lists no known hazards. This does not mean that every use is safe.