Water mint
Mentha aquatica
A strongly aromatic wetland mint growing 30–90cm tall, with square, often purple-flushed stems and hairy, stalked, toothed leaves. The flowers sit in a dense rounded lilac head at the top of the stem rather than a tapering spike, which is the quickest way to place it. Used like garden mint in teas, sauces and cold drinks, though the flavour is coarser and muskier. It is one parent of peppermint.
Wet ground and shallow water — pond and lake margins, ditches, canal banks, marshes, fens, wet meadows and flushes in damp woodland. Spreads by rooting runners into broad patches. Common and widespread throughout Britain and Ireland.
Safe in normal culinary amounts as a leaf or a tea. It grows in still and slow-moving water, so plants below grazing land or arable runoff can carry contamination — pick from clean water, rinse thoroughly, or cook. Concentrated mint oils are not the same thing as leaf tea.
Always use more than one reference to confirm a plant. You are responsible for what you choose to forage.
Flower head
A single dense, rounded head of lilac to mauve flowers about 2cm across, sitting at the very top of the stem, sometimes with one or two smaller whorls just below it. Spearmint and peppermint carry their flowers in a tapering spike instead.
Position in the landscape
Grows with its base in wet mud or standing water, often leaning out over the margin of a ditch or pond. A mint found rooted in open water is far more likely to be this than any of the dry-ground mints.
Stem
Square in cross-section, erect, 30–90cm, frequently flushed reddish-purple and softly hairy, rising from creeping runners that root as they go and form large patches.
Leaves
Opposite pairs of ovate, toothed leaves on clear stalks, hairy on both surfaces and often bronze or purple-tinged. The stalk and the hairiness together separate it from the near-stalkless, smoother leaves of spearmint.
Scent when crushed
Crushing a leaf gives a strong, sweet, slightly musty peppermint scent that carries on the fingers. No aromatic scent at all means the plant is not a mint, whatever the habitat suggests.
Updated 2026-08-08T07:14:29.211Z · Part of the shared Foragers Log catalogue · Herb