Peppermint (Mentha piperita)

Peppermint is a hybrid mint, a cross between the watermint (Mentha aquatica) and spearmint (Mentha spicata). The plant is indigenous in Europe and now widespread in cultivation throughout all regions of the world. It is a herbaceous rhizomatous perennial plant growing to 30–90 cm (12–35 in) tall, with smooth stems, square in cross section. The rhizomes are wide-spreading, fleshy, and bare fibrous roots. The leaves are from 4–9 cm (1.6–3.5 in) long and 1.5–4 cm (0.59–1.6 in) cm broad, dark green with reddish veins, and with an acute apex and coarsely toothed margins. The leaves and stems are usually slightly hairy. The flowers are purple, 6–8 mm (0.24–0.31 in) long, with a four-lobed corolla about 5 mm (0.20 in) diameter; they are produced in whorls (verticillasters) around the stem, forming thick, blunt spikes. Flowering is from mid to late summer.

How to grow
Peppermint generally thrives in shade and expands quickly by underground rhizomes. If you choose to grow peppermint, it is advisable to plant it in a container, otherwise it can rapidly take over a whole garden. It needs a good water supply, and is ideal for planting in part-sun to shade areas. Sow the seed directly into the soil and cover with 1/4 inch of soil, use a rich, well-drained, acidic to neutral soil. Prefer full sun, keep soil moderately moist during germination. The germination time is 1 to 3 weeks.

Uses
Peppermint is most excellent for tea because it has a sweeter scent than other mints. Peppermint tea, brewed from the plant leaves, and the essential oil of peppermint are used in traditional medicines. The main volatile components of the essential oil are menthol and menthone. In vitro, peppermint has significant antimicrobial and antiviral activities, strong antioxidant and antitumor actions, and some antiallergenic potential.