Mimosa pudica aka Touch Me Not

Mimosa pudica is known as sensitive plant or touch-me-not. It belongs to the pea family, Fabaceae. Its native range runs from Mexico through tropical America. It now grows across tropical regions beyond its native range. It lives in fields, pastures, orchards, and along roads. It also grows on moist waste ground and disturbed sites. Plants may stand alone or form tangled patches. Useful Tropical Plants reports its conservation status as Least Concern.

This plant can grow as an annual or short-lived perennial. In warm conditions, it keeps its leaves year-round. Its low stems creep and spread across the ground. Garden plants reach about 0.3–1.6 feet [0.1–0.5 metres] tall. Their spread reaches 1.6–3.3 feet [0.5–1 metre]. Some plants reach 3.3 feet [1 metre] in height. The stems bear spines and can become woody with age. The divided leaves droop when touched, giving the plant its name. Soft-looking flower heads appear in summer, in pale pink or purple. The ripe fruits split open and release seeds.

Warmth is central to its care, since frost damages it. The RHS gives it the UK hardiness rating H1B. Plants For A Future lists USDA zones 10–12. In Britain, it suits a heated glasshouse or summer patio pot. The RHS advises winter temperatures of at least 13°C. Give it strong light, with shade from hot sun. Use moist, well-drained loam or a peat-free, loam-based potting mix. It accepts acid, neutral, and alkaline soil. Water moderately during growth, then reduce water in winter. Apply balanced liquid feed each month during the growing season.

Its moving leaves make it a useful plant for close viewing. It also serves as ground cover in warm regions. Growers use it as green manure and to limit soil erosion. It has potential for cleaning arsenic-polluted ground. These uses do not remove its risk of becoming a weed. The RHS reports few disease problems, though glasshouse red spider mites can attack. It needs no pruning. Sow soaked seeds in spring at 18–24°C. Early-summer softwood cuttings need heat beneath the rooting medium.

Plants For A Future records edible and traditional medicinal uses. The scented flowers can be candied or made into distilled flower water. The seeds yield an oil compared with soybean oil. Traditional medicine uses the roots for several complaints, including asthma and inflammation. These records do not establish that such treatments work. Large root doses are toxic. Hard prickles on stems and fruits can inflame grazing animals' intestines.