Mentha (also known as mint, from Greek míntha, Linear B mi-ta) is a genus of plants in the family Lamiaceae (mint family). The species are not clearly distinct, and estimates of their number vary from 13 to 18.Hybridization between some of the species occurs naturally. Many other hybrids, as well as numerous cultivars, are known.
The genus has a subcosmopolitan distribution across Europe, Africa, Asia, Australia, and North America.
Mints are aromatic, almost exclusively perennial, rarely annual, herbs. They have wide-spreading underground and overground stolons and erect, square, branched stems. The leaves are arranged in opposite pairs, from oblong to lanceolate, often downy, and with a serrated margin. Leaf colors range from dark green and gray-green to purple, blue, and sometimes pale yellow. The flowers 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.
While the species that make up the Mentha genus are widely distributed and can be found in many environments, most grow best in wet environments and moist soils. Mints will grow 10–120 cm tall and can spread over an indeterminate area. Due to their tendency to spread unchecked, some mints are considered invasive.
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 — one might not end up with what one supposed was planted — 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 (Mentha × piperita), native spearmint (Mentha spicata), Scotch spearmint (Mentha x gracilis), and cornmint (Mentha arvensis); also (more recently) apple mint (Mentha suaveolens).
Mints are supposed to make good companion plants, repelling pesty insects 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.