Spearmint is a perennial herbaceous plant. It is 30–100 cm (12–39 in) tall, with variably hairless to hairy stems and foliage, and a wide-spreading fleshy underground rhizome from which it grows. The leaves are 5–9 cm (2– 3 1⁄2 in) long and 1.5–3 cm (1⁄2 – 1 1⁄4 in) broad, with a serrated margin.