Spearmint (Mentha spicata), also known as garden mint, common mint, lamb mint and mackerel mint, is native to Europe and southern temperate Asia, extending from Ireland in the west to southern China in the east. It is naturalized in many other temperate parts of the world, including northern and southern Africa, North America, and South America. It is used as a flavouring in food and herbal teas. The aromatic oil, called oil of spearmint, is also used as a flavoring and sometimes as a scent.
The species and its subspecies have many synonyms, including Mentha crispa, Mentha crispata, and Mentha viridis.
Description
thumb|Spearmint in Bangladesh
Spearmint is a perennial herbaceous plant. It is tall, with variably hairless to hairy stems and foliage, and a wide-spreading fleshy underground rhizome from which it grows. The leaves are long and broad, with a serrated margin. The stem is square-shaped, a defining characteristic of the mint family of herbs. Spearmint produces flowers in slender spikes, each flower pink or white in colour, long and broad. Spearmint flowers in the summer (from July to September in the northern hemisphere), and has relatively large seeds, which measure .
Mentha spicata varies considerably in leaf blade dimensions, the prominence of leaf veins, and pubescence.
Taxonomy
Mentha spicata was first described scientifically by Carl Linnaeus in 1753. The species has two accepted subspecies, each of which has acquired a large number of synonyms: which could be a result of hybridization and chromosome doubling. Mentha longifolia and Mentha suaveolens (2n = 24) are likely to be the contributing diploid species.
- Mentha × piperita (hybrid with Mentha aquatica), black peppermint, hairy peppermint
- Mentha × gracilis (hybrid with Mentha arvensis), Scotch spearmint
- Mentha × villosa (hybrid with Mentha suaveolens)
Varieties and cultivars
There are several commonly available varieties and cultivars of Mentha spicata:
- M. spicata var. crispa (syn. M. spicata 'Crispa') – with very crinkled leaves. Further records show descriptions of mint in ancient mythology.
Spearmint is documented as being an important cash crop in Connecticut during the period of the American Revolution, at which time mint tea was noted as being a popular drink due to it not being taxed.
Spearmint ideally thrives in soils that are deep, well-drained, moist, rich in nutrients and organic matter, and have a crumbly texture. The pH range should be between 6.0 and 7.5.
Diseases and pests
Fungal diseases
Fungal diseases are common diseases in spearmint. Two main diseases are rust and leaf spot. Puccinia menthae is a fungus that causes the disease called "rust". Rust affects the leaves of spearmint by producing pustules inducing the leaves to fall off. Leaf spot is a fungal disease that occurs when Alternaria alernata is present on the spearmint leaves. The infection looks like circular dark spot on the top side of the leaf. Other fungi that cause disease in spearmint are Rhizoctonia solani, Verticillium dahliae, Phoma strasseri, and Erysiphe cischoracearum.
Nematode diseases
Some nematode diseases in spearmint include root knot and root lesions. Nematode species that cause root knots in this plant are various Meloidogyne species. The other nematode species are Pratylenchus which cause root lesions. Gardeners often grow it in pots or planters due to its invasive, spreading rhizomes.
Spearmint leaves can be used fresh, dried, or frozen. The leaves lose their aromatic appeal after the plant flowers. It can be dried by cutting just before, or right (at peak) as the flowers open, about one-half to three-quarters the way down the stalk (leaving smaller shoots room to grow). Some dispute exists as to what drying method works best; some prefer different materials (such as plastic or cloth) and different lighting conditions (such as darkness or sunlight). The leaves can also be preserved in salt, sugar, sugar syrup, alcohol, or oil.
Oil uses
Spearmint is used for its aromatic essential oil, called oil of spearmint. The most abundant compound in spearmint oil is R-(–)-carvone, which gives spearmint its distinctive "minty, green, cooling, spicy" smell. Spearmint oil also contains significant amounts of limonene, dihydrocarvone, and 1,8-cineol. Unlike oil of peppermint, oil of spearmint contains minimal amounts of menthol and menthone. It is used as a flavouring for toothpaste and confectionery, and is sometimes added to shampoos and soaps.
Traditional medicine
Spearmint has been used in traditional medicine.
Used as a fumigant, spearmint essential oil is an effective insecticide against adult moths.
Antimicrobial research
Spearmint has been used for its supposed antimicrobial activity, which may be related to carvone. Its in vitro antibacterial activity has been compared to that of amoxicillin, penicillin, and streptomycin.
Beverages
Spearmint leaves are infused in water to make spearmint tea. Spearmint is an ingredient of Maghrebi mint tea. Grown in the mountainous regions of Morocco, this variety of mint possesses a clear, pungent, but mild aroma. Spearmint is an ingredient in several cocktails, such as the mojito and mint julep. Sweet tea, iced and flavored with spearmint, is a summer tradition in the Southern United States. In Western Australia, green-coloured, spearmint-flavored milk is a local treat.
Gallery
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File:Mentha spicata, Serbia.jpg|Mentha spicata
Image:mentha spicata 02.jpg|Plant in flower
Image:Flowers of the spearmint.JPG|Flowers
Image:Spearmint flower.jpg|White flowering whorls of a spearmint plant
Image:Mentha spicata 01.jpg
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