Common Name: Water Mint

General Information

Mentha aquatica is an erect, herbaceous perennial plant growing from a spreading, rhizomatous rootstock. It forms a loose cluster of branched stems that can grow from 50 - 150cm tall[].
The plant is harvested from the wild for local use as a food, medicine and source of materials. Water mint has been cultivated for probably more than 2,000 years for use as an aromatic and medicinal plant and is stillgrown in a small scale, especially a glabrous form that is grown in northern Italy as a source of the essential oil linalool[].

Known Hazards

Although no records of toxicity have been seen for this species, large quantities of some members of this genus, especially when taken in the form of the extracted essential oil, can cause abortions so some caution is advised.

Botanical References

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Range

Throughout Europe, except northern Russia, to the Caucasus and Iran; West Siberia, Mediterranean Africa, east and south Africa

Habitat

Swamps, fen, marshes, near rivers, streams and ponds, in wet woods[].

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Perennial
Height	1.00 m
Pollinators	Bees, Lepidoptera, Insects
Cultivation Status	Wild

Cultivation Details

Mentha aquatica is a moderately cold-hardy plant, able to tolerate temperatures down to around -20°c when fully dormant[200
Succeeds in most soils and situations so long as the soil is not too dry[, , ]. Grows well in heavy clay soils. A sunny position is best for production of essential oils, but it also succeeds in partial shade. Plants can grow in water up to 15cm deep[].
Mentha species are very prone to hybridisation and so the seed cannot be relied on to breed true. Even without hybridisation, seedlings will often not be uniform and so the content of medicinal oils etc will vary. When growing plants with a particular aroma it is best to propagate them by division[].
Most mints have fairly aggressive spreading roots and, unless you have the space to let them roam, they need to be restrained by some means such as planting them in containers that are buried in the soil[].
The leaf shape of this species is very variable - one of the reasons for the very long list of synonyms given above!. All specimens found in east Africa have hermaphrodite flowers with exserted anthers. Individuals with functionally female flowers, with included stamens, occur widely elsewhere[].
Hybridizes freely with other members of this genus.
The whole plant, especially when bruised, has a pungent aroma of bergamot[].
Members of this genus are rarely if ever troubled by browsing deer[].

Edible Uses

Leaves - raw or cooked. A strong distinctive peppermint-like fragrance[]. Used as a flavouring in salads or cooked foods[]. The leaves are too pungent for most people to use as a flavouring[].

A herb tea is made from the leaves[, ].

Medicinal

The leaves are anodyne, antiseptic, antispasmodic, astringent, carminative, cholagogue, diaphoretic, emetic, refrigerant, stimulant, stomachic, tonic and vasodilator[, , ]. A tea made from the leaves has traditionally been used in the treatment of fevers, headaches, digestive disorders and various minor ailments[]. It is also used as a mouth-wash and a gargle for treating sore throats, ulcers, bad breath etc[].
The leaves are harvested as the plant comes into flower and can be dried for later use[].

The essential oil in the leaves is antiseptic, though it is toxic in large doses[].

Agroforestry Uses:

Mint species are usually good bee and butterfly attractant plants, supplying them with good quality pollen and nectar[]
Mints are usually quite aromatic plants and they make good companions for cabbages and tomatoes, their aromatic nature helping to repel insect pests..

Other Uses

The plant repels flies, mice and rats[, , ]. It has a pleasant, fresh scent and was formerly used as a strewing herb and has been strewn in granaries to keep mice and rats off the grain[, ].

The plant, harvested before flowering, yields about 0.8% essential oil[]. The fresh or dried plant is very good when used in herbal baths and can also be used in herb pillows[].

Propagation

Seed - sow spring in a cold frame. Germination is usually fairly quick. Prick out the seedlings into individual pots when they are large enough to handle and plant them out in the summer. Mentha species are very prone to hybridisation and so the seed cannot be relied on to breed true. Even without hybridisation, seedlings will not be uniform and so the content of medicinal oils etc will vary. When growing plants with a particular aroma it is best to propagate them by division[].
Division can be easily carried out at almost any time of the year, though it is probably best done in the spring or autumn to allow the plant to establish more quickly. Virtually any part of the root is capable of growing into a new plant. Larger divisions can be planted out direct into their permanent positions. However, for maximum increase it is possible to divide the roots up into sections no more than 3cm long and pot these up in light shade in a cold frame. They will quickly become established and can be planted out in the summer.