Spearmint is a perennial herbaceous plant. It is 30–100 cm tall. The leaves are 5–9 cm long and 1.5–3 cm broad, with a serrated margin. The stem is square-shaped, a defining characteristic of the mint family of herbs. each flower pink or white in colour, 2.5–3 mm long and broad.  

It is native to  Europe and southern temperate Asia, extending from Ireland in the west to southern China in the east.