Mentha


Mentha, also known as mint, is a genus of flowering plants in the mint family, Lamiaceae. It is estimated that 13 to 24 species exist, but the exact distinction between species is unclear. Hybridization occurs naturally where some species' ranges overlap. Many hybrids and cultivars are known.
The genus has a subcosmopolitan distribution, growing best in wet environments and moist soils.

Description

Mints are aromatic, almost exclusively perennial herbs. They have wide-spreading underground and overground stolons and erect, square, branched stems. Mints will grow tall and can spread over an indeterminate area. Due to their tendency to spread unchecked, some mints are considered invasive.
The leaves are arranged in opposite pairs, from oblong to lanceolate, often downy, and with a serrated margin. Leaf colours range from dark green and gray-green to purple, blue, and sometimes pale yellow.
The flowers are produced in long bracts from leaf axils. They are white to purple and produced in false whorls called verticillasters. The corolla is two-lipped with four subequal lobes, the upper lobe usually the largest. The fruit is a nutlet, containing one to four seeds.

Taxonomy

Mentha is a member of the tribe Mentheae in the subfamily Nepetoideae. The tribe contains about 65 genera, and relationships within it remain obscure. Authors have disagreed on the circumscription of Mentha. For example, M. cervina has been placed in Pulegium and Preslia, and M. cunninghamii has been placed in Micromeria. In 2004, a molecular phylogenetic study indicated that both M. cervina and M. cunninghamii should be included in Mentha. However, M. cunninghamii was excluded in a 2007 treatment of the genus.
More than 3,000 names have been published in the genus Mentha, at ranks from species to forms, the majority of which are regarded as synonyms or illegitimate names. The taxonomy of the genus is made difficult because many species hybridize readily, or are themselves derived from possibly ancient hybridization events. Seeds from hybrids give rise to variable offspring, which may spread through vegetative propagation. The variability has led to what has been described as "paroxysms of species and subspecific taxa"; for example, one taxonomist published 434 new mint taxa for central Europe alone between 1911 and 1916. Recent sources recognize between 18 and 24 species.

Species

, Plants of the World Online recognized the following species:
  • Mentha alaica Boriss.
  • Mentha aquatica L. – water mint, marsh mint
  • Mentha arvensis L. – corn mint, wild mint, Japanese peppermint, field mint, banana mint
  • Mentha atrolilacina B.J.Conn & D.J.Duval – slender mint
  • Mentha australis R.Br. – Australian mint
  • Mentha canadensis L. – Canada mint, American wild mint
  • Mentha cervina L. – Hart's pennyroyal
  • Mentha choujunensis A.H.Ganie, T.Islam & Khuroo
  • Mentha cunninghamii Benth. – New Zealand mint
  • Mentha dahurica Fisch. ex Benth. – Dahurian thyme
  • Mentha darvasica Boriss.
  • Mentha diemenica Spreng. – slender mint
  • Mentha gattefossei Maire
  • Mentha grandiflora Benth.
  • Mentha japonica Makino
  • Mentha laxiflora Benth. – forest mint
  • Mentha longifolia L. – horse mint
  • Mentha micrantha Heinr.Braun
  • Mentha pamiroalaica Boriss.
  • Mentha pulegium L. – pennyroyal
  • Mentha requienii Benth. – Corsican mint
  • Mentha royleana Wall. ex Benth.
  • Mentha satureioides R.Br. – native pennyroyal
  • Mentha spicata L. – spearmint, garden mint
  • Mentha suaveolens Ehrh. – apple mint, pineapple mint

    Hybrids

The mint genus has a large grouping of recognized hybrids. Those accepted by Plants of the World Online are listed below. Parent species are taken from Tucker & Naczi. Synonyms, along with cultivars and varieties where available, are included within the specific nothospecies.
  • Mentha × carinthiaca Host – M. arvensis × M. suaveolens
  • Mentha × dalmatica Tausch – M. arvensis × M. longifolia
  • Mentha × dumetorum Schult. – M. aquatica × M. longifolia
  • Mentha × gayeri Trautm. – M. longifolia × M. spicata × M. suaveolens
  • Mentha × gracilis Sole – M. arvensis × M. spicata – ginger mint, Scotch spearmint
  • Mentha × kuemmerlei Trautm. – M. aquatica × M. spicata × M. suaveolens
  • Mentha × locyana Borbás – M. longifolia × M. verticillata
  • Mentha × piperita L. – M. aquatica × M. spicata – peppermint, chocolate mint
  • Mentha × pyramidalis Ten. – M. aquatica × M. microphylla
  • Mentha × rotundifolia Huds. – M. longifolia × M. suaveolens – false apple mint
  • Mentha × suavis Guss. – M. aquatica × M. suaveolens
  • Mentha × verticillata L. – M. aquatica × M. arvensis
  • Mentha × villosa Huds. – M. spicata × M. suaveolens – large apple mint, foxtail mint, hairy mint, woolly mint, Cuban mint, mojito mint, and yerba buena in Cuba
  • Mentha × villosa-nervata Opiz – M. longifolia × M. spicata – sharp-toothed mint
  • Mentha × wirtgeniana F.W.Schultz – M. aquatica × M. arvensis × M. spicata – red raripila mint

    Common names and cultivars

There are hundreds of common English names for species and cultivars of Mentha. These include:
  • Apple mint – Mentha suaveolens and Mentha × rotundifolia
  • Banana mint – Mentha arvensis 'Banana'
  • Bowles mint – Mentha villosa and Mentha × villosa 'Alopecuroides'
  • Canada mint – Mentha canadensis
  • Chocolate mint – Mentha × piperita 'Chocolate'
  • Corsican mint – Mentha requienii
  • Cuba mint – Mentha × villosa
  • Curly mint – Mentha spicata 'Curly'
  • Eau de Cologne mint – Mentha × piperita 'Citrata'
  • Field mint – Mentha arvensis
  • Flea mint – Mentha requienii
  • Ginger mint – Mentha × gracilis
  • Gray mint – Mentha longifolia
  • Green mint – Mentha spicata
  • Grey mint – Mentha longifolia
  • Japanese peppermint – Mentha arvensis var. piperascens
  • Japanese mint or Japanese medicine mint – Mentha spicata 'Abura'
  • Kiwi mint – Mentha cunninghamii
  • Lemon mint – Mentha × piperita var. citrata and Mentha × gentilis
  • Marsh mint – Mentha aquatica
  • Meadow mint – Mentha × gracilis and Mentha arvensis
  • Mojito mint – Mentha spicata 'Mojito'
  • Moroccan mint – Mentha spicata var. crispa 'Moroccan' and mints collected in Morocco
  • Pennyroyal – Mentha pulegium
  • Peppermint – Mentha × piperita and sometimes Mentha requienii
  • Pineapple mint – Mentha suaveolens 'Variegata' and Mentha suaveolens 'Pineapple'
  • Polemint – Mentha pulegium
  • Red raripila mint – Mentha × wirtgeniana
  • Round leaf mint – Mentha suaveolens
  • Spearmint – Mentha spicata
  • Strawberry mint – Mentha × piperita 'Strawberry'
  • Swiss mint – Mentha × piperita 'Swiss'
  • Tall mint – Mentha × wirtgeniana
  • Tea mint – Mentha × verticillata
  • Toothmint – Mentha × smithiana
  • Water mint – Mentha aquatica
  • Woolly mint – Mentha × ''rotundifolia''

    Distribution and habitat

The genus has a subcosmopolitan distribution across Europe, Africa –, Asia, Australia – Oceania, North America and South America. Its species can be found in many environments, but most grow best in wet environments and moist soils.

Ecology

Mints are used as food by the larvae of some Lepidoptera species, including buff ermine moths, and by beetles, such as Chrysolina coerulans and C. herbacea.

Diseases

Cultivation

All mints thrive near pools of water, lakes, rivers, and cool moist spots in partial shade. In general, mints tolerate a wide range of conditions, and can also be grown in full sun. Mint grows all year round.
They are fast-growing, extending their reach along surfaces through a network of runners. Due to their speedy growth, one plant of each desired mint, along with a little care, will provide more than enough mint for home use. Some mint species are more invasive than others. Even with the less invasive mints, care should be taken when mixing any mint with any other plants, lest the mint take over. To control mints in an open environment, they should be planted in deep, bottomless containers sunk in the ground, or planted above ground in tubs and barrels.
Some mints can be propagated by seed, but growth from seed can be an unreliable method for raising mint for two reasons: mint seeds are highly variable and some mint varieties are sterile. It is more effective to take and plant cuttings from the runners of healthy mints.
The most common and popular mints for commercial cultivation are peppermint, native spearmint, Scotch spearmint, and cornmint ; also apple mint.
Mints are supposed to make good companion plants, repelling insect pests and attracting beneficial ones. They are susceptible to whitefly and aphids.
Harvesting of mint leaves can be done at any time. Fresh leaves should be used immediately or stored up to a few days in plastic bags in a refrigerator. Optionally, leaves can be frozen in ice cube trays. Dried mint leaves should be stored in an airtight container placed in a cool, dark, dry area.