Despite its name, Pycnanthemum virginianum is less a creature of rocky summits than of sunny meadows and moist roadsides across eastern North America. Growing two to three feet tall with small, intensely aromatic leaves, it blooms in midsummer in a sequence that spirals inward from the outer ring of white, purple-dotted flowers toward the center, giving any colony a weeks-long season of interest. The genus name translates from Greek as dense flower, and dense is exactly the right word for both the blooms and the insect activity they provoke.

In the garden it thrives in full or partial sun and tolerates an almost perverse range of soils, from sandy gravel to heavy clay, though it is more politely behaved in drier conditions than in optimum moist sites where the rhizomes can spread assertively. A short distance from the mother plant it will form loose colonies that weave well into a naturalized border or meadow planting. Mammals and leaf-chewing insects avoid it reliably, apparently put off by the same mint fragrance that makes it so pleasant to brush against on a summer walk.