1、 Blade difference

Water mint leaves are long ovate to elliptic lanceolate, about 3-7 cm long, with sharp apex, broad wedge-shaped base, thin and sharp serrations on the edge, pubescence on the top and pilose and glandular spots below

The leaves of peppermint are usually lanceolate, elliptic or oblong lanceolate, rarely oblong, similar in size to the former, the apex is also acute, the base is wedge-shaped, then to nearly circular, the edge is toothed sawtooth, both sides have hair, and there are no gland points below

2、 The difference between flowers

Water Mint cymes grow in leaf axils, bracts are linear lanceolate, bell shaped calyx, 5-lobed, lobes are nearly triangular, and corolla is light red or purple, sometimes white

Peppermint inflorescence is the same as the former. The calyx is tubular bell shaped, 5 calyx teeth, narrow triangular subulate, and the Corolla is light purple