Blephilia ciliata aka Downy Wood Mint

Blephilia ciliata belongs to the mint family, Lamiaceae. It is a perennial, a plant that lives for years. Its names include Ohio horsemint and downy wood mint. It grows wild in the central and eastern United States. Reports place it as far as Canada, Georgia, and Oklahoma. It grows in dry woods, prairies, and clearings. It also grows in fields and by roads. Wild plants also grow in thin soil over limestone.

This short-lived plant grows fast and forms upright clumps. It reaches 1–2.5 feet [0.30–0.76 metres] tall. Clumps spread about 0.67–1.5 feet [0.20–0.46 metres] wide. Its shallow roots form fine strands and limit its spread. The stout stems are square and bear short white hairs. Most stems do not branch unless damage spurs side shoots. Green leaves grow in pairs on opposite sides of stems. Leaves range from oblong to lanceolate, or lance-shaped. Their clear pinnate veins branch from a main central vein. White hairs coat the leaves, most so on their undersides. Lower leaves have short stalks, but upper leaves have none. Crushed leaves give off a mild scent.

Flowers bloom from late spring into summer, within May through August. Each plant may bloom for about one month. Round groups of flowers form spaced tiers up the stem. Bracts, or small leaf-like parts, sit beneath each group. Hairs form a fringe along these bracts. The small flowers have two lips, with purple spots below. Most blooms are blue-purple; some are white or pale pink. Bees and flies visit, as do butterflies and skippers. The dry fruit stays closed when it ripens.

Grow Ohio horsemint in full sun or partial shade. Give it soil that drains well. Soil can range from dry to moderately moist. It grows in loam, clay, sand, and soil with gravel. Sources give acidic through neutral soil and pH 6–8. It copes with some drought, but not with flooded ground. It cannot cope with soil that stays full of water. Salt and packed soil also cause problems. It is hardy in USDA zones 4–8. Divide clumps to make more plants.

Use it in native gardens, meadows, and open woods. Plant groups offer blooms for pollinators that visit them. It needs a fair amount of care. Leaves can look ragged late in the season. Powdery mildew can harm leaves, and insects may chew them. Aphids, mites, and thrips may also cause trouble. Other possible pests are whiteflies and leafminers. The mint-flavoured leaves are edible raw or brewed as tea. They can also flavour sauces and other drinks. Sources do not establish whether pets can eat it safely. Nor do they establish the safety of other plant parts.