Pycnanthemum tenuifolium is an herbaceous plant with wiry, green, branching stems from 0.6–0.9 metres (2–3 ft) tall.

[2] The flowers are white, borne in dense, half-round heads in summer, June through September.

[3] Unlike most plants in the genus, the foliage has a very faint mint fragrance.

[4] Pycnanthemum is based on the Greek words pyknós (dense) and ανθέμιον (flower).

Native habitats include dry, open, rocky woods, dry prairies and fields, roadsides, pine barrens, streams, and open wet thickets.