Watermint (Mentha aquatica): The Wild Parent of Peppermint

One of peppermint’s two parents grows wild along ditches and streams. Watermint (Mentha aquatica) is a mint of wet ground across Europe, Africa and western Asia, and in Britain it turns up in almost every 10 km square outside the Scottish Highlands.¹ It smells unmistakably of mint, but its oil is put together differently from peppermint’s: in the samples that have been measured, the main compound is menthofuran, not menthol.²³ Few cooks ever buy it.

At a glance

Flavor and the compounds behind it

Watermint tastes strongly minty, with a musty, slightly medicinal edge and less of peppermint’s clean cooling. The chemistry helps explain why it’s different:

The two water mint studies agree that menthofuran leads, but not on how much. They tested different plants in different places and years, and neither figure describes water mint in general. Menthol, the compound that dominates peppermint oil, isn’t among the main components either study reports.²³

Origin and relatives

Water mint is native to Africa and from Europe to central Siberia and western Asia, a perennial of the temperate biome. It’s native in Britain and Ireland. The BSBI’s Plant Atlas 2020 finds it in almost every 10 km square outside the Scottish Highlands, in ditches, ponds, rivers, marshes, fens, dune slacks and wet woods, from sea level to 490 m (about 1,600 feet).¹ You’ll often read that Roman soldiers brought it to Britain. The BSBI’s native status for the plant doesn’t support that.

Peppermint is a natural cross between water mint and spearmint. Katzer adds that the hybrid is usually sterile.⁶ Kew also lists Mentha citrata, the plant sold as orange or bergamot mint, as a synonym of Mentha aquatica.⁴ See orange mint and chocolate mint.

Myth and history. Strabo records the Greek story of Minthe, the nymph trampled by Persephone (Core) and turned into a mint plant, and calls the plant garden-mint.⁷ No source we found says it was water mint. Claims that water mint was the mint of Ovid’s Philemon and Baucis, a Roman funeral herb, a bath scent or a medieval strewing herb couldn’t be traced to a source, so we’ve left them out.

How it is used

We didn’t find a cookbook or culinary reference that treats water mint as its own kitchen herb. Its uses follow from its flavor:

• Tea. Fresh leaves steeped in hot water, alone or with other mints.
• In place of other mint. Small amounts in sauces, salads or drinks. Go lighter than you would with spearmint, since it’s musty and strong.

Like other mints, it loses flavor and aroma with long cooking. Mint is one of the delicate herbs to add a minute or two before cooking ends. For general technique see cooking with mint and mint uses.

Gathering. If you forage it, be sure of your identification and pick from clean water.

Buying and storage

You’ll usually buy water mint as a live plant, not as a cut herb. Store and preserve it like other fresh mint: see how to store mint, can you freeze mint? and how to dry mint. We found no storage study specific to water mint.

Health and safety

We found no NIH summary, regulator monograph or human trial on water mint. The research on mint and health is about peppermint oil, mainly enteric-coated capsules for irritable bowel syndrome, and NCCIH notes that very little research has been done even on peppermint leaf.⁸ Claims that water mint calms anxiety, aids digestion or fights cancer have no human evidence behind them, and we’re not making any.

There’s one chemical point to know about. Water mint’s main oil compound, menthofuran, is one of two compounds (with pulegone) for which the European Medicines Agency, assessing peppermint medicines, accepted a combined intake of up to 37.5 mg per day for a 50 kg adult.⁹ That assessment covers peppermint products, not water mint, and we found no study measuring menthofuran in a cup of water mint tea.

Substitutes and comparisons

Peppermint is the closest substitute in cooking. Spearmint gives you something sweeter and softer. Related pages:

• Mint, peppermint and spearmint; spearmint vs. peppermint
• Types of mint
• Mint substitutes and too much mint