Common Name: American Wild Mint

General Information

Mentha canadensis is an erect, perennial plant producing a clump of annual stems 60 - 100cm tall from rapidly spreading, underground rhizomes[].
This is the only species of mint with forms that are truly adapted to tropical areas. It is harvested from the wild, whilst selected forms are often cultivated both in the home garden and commercially, as a medicine, food and source of essential oil for flavouring etc.

Mentha haplocalyx is frequently cultivated in E and S Asia for the essential oils of the leaves which are rich in menthol; after World War II grown also in Brazil, Argentina, USA, Seychelles, India (Jammu and Kashmir) and Europe (especially in Spain and Hungary), in Africa cultivated in trials. Commonly planted as an aromatic and medicinal plant in E and SE Asia, New Zealand, Cuba and Mexico. Also used as a pot herb. Menthol is used for the production of tooth paste, mouth water, cosmetical and pharmazeutical preparations and for flavouring cigarettes. Oil without menthol can be used for perfumes and other cosmetics. The delimitation of the species is still under discussion. By some authors it is considered as a very polymorphous complex species with different chromosomal races (2n=24 to 2n=108) and chemotypes (3-octan, pulegon, menthon - menthol) whereas other authors tend to separate this complex into two to four different species.

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

Asia - western Siberia, south through Myanmar to Indonesia, east to Japan, Philippines; Americas - Alaska to Newfoundland, south to Guatemala, Florida

Habitat

Moist places at low to moderate elevations in N. America[]. Wet areas throughout China at elevations from sea level to 3,500 metres[].

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Perennial
Height	0.60 m
Pollinators	Bees, Lepidoptera, Insects
Cultivation Status	Cultivated, Wild

Cultivation Details

Mentha canadensis is a plant mainly of the temperate and subtropical zones, though in its various forms it grows from the temperate zone through to the tropics. It grows best in areas where annual daytime temperatures are within the range 10 - 25°c, but can tolerate 3 - 30°c[]. When dormant, the plant can survive temperatures down to about -8°c, but young growth can be severely damaged at -1°c[]. Plants are hardy to at least -15°c[]. It prefers a mean annual rainfall in the range 800 - 1,100mm, but tolerates 500 - 4,300mm[].
A sunny position is best for production of essential oils, but the plant also succeeds in partial shade. An easily grown plant, it succeeds in most soils and situations so long as the soil is not too dry[, , ]. This species tolerates much drier conditions than other members of the genus[]. Prefers a slightly acid soil[]. Grows well in heavy clay soils.
Prefers a pH in the range 5.5 - 6.4, tolerating 4.5 - 8.3[].
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[].
Hybridizes freely with other members of this genus.
The whole plant has a very strong scent of peppermint[].
Members of this genus are rarely if ever troubled by browsing deer[].
When grown commercialy as a source of essential oil, plants can remain productive for 5 - 6 years[]. However, oil production is reduced in warmer climates and most tropical regions are not suitable for commercial production[].

Edible Uses

Leaves - raw or cooked. Used as a flavouring in salads or cooked foods[, , ]. The leaves can vary widely in flavour with some forms of the plant having a mild flavour whilst others can have a strong taste of peppermint[, ].

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

An essential oil from the plant is used as a flavouring in sweets and beverages[]. The leaves contain about 0.2% essential oil[].

Medicinal

American wild mint, like many other members of this genus, is often used as a domestic herbal remedy, being valued especially for its essential oil[] which has antiseptic properties and a beneficial effect on the digestion. Like other members of the genus, it is best not used by pregnant women because large doses can cause an abortion.

The whole plant is anaesthetic, antiphlogistic, antispasmodic, antiseptic, aromatic, carminative, diaphoretic, emmenagogue, galactofuge, refrigerant, stimulant, stomachic and vasodilator[, , , ]. A tea made from the leaves has traditionally been used in the treatment of fevers, headaches, digestive disorders and various minor ailments[222,279]. The leaves are a classical remedy for stomach cancer[].
Applied externally, the leaves are used to treat skin conditions, cuts and wounds, insect stings etc[]. They have been used in a poultice to ease headaches[].
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 is used as an insect repellent[, , ]. Rats and mice intensely dislike the smell of mint. The plant was therefore used in homes as a strewing herb and has also been spread in granaries to keep the rodents off the grain[]. The leaves also repel various insects[].

An essential oil is extracted from its leaves. This oil contains 60 - 85% menthol and is used medicinally and as a flavouring in pharmaceutical products; as a flavouring in products such as toothpastes, various foods, cigarettes, and alcoholic beverages; and as a perfume in products such as soaps, lotions and cologne[, ]. It can be used as a substitute for, or adulterant of, peppermint oil[]. Yields of up to 1.6% have been obtained[].

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.