Mimosa pudica, the 'sensitive plant', is a source of fascination to adults and children alike. When touched, the narrow fern-like leaflets they almost instantaneously fold together and the leaf stalk droops. This sometimes sets off a chain reaction, with several leaf stalks falling on top of one another.
The plant will gradually returns to normal, taking up to about half an hour. This touch-induced movement of leaves is known scientifically as thigmonasty, and is thought to be a defensive mechanism against grazers. At night, the leaves will also fold and bend in movements known as nyctonastic movements (reaction to absence of light).
The plant flowers have clusters of five to eight fluffy, ball-shaped pale mauve-pink flowers on short stalks. Each flower consists of hundreds of fine filaments, giving it the appearance of a fluffy pompon.
In temperate climates, it is grown mainly as an indoor plant, usually for its fascinating behaviour. In its natural environment it is a shrub-like plant, growing to a height of about 60cm. M. pudica comes from tropical places and when grown in a temperate climate, it is best thought of as a very short-lived plant if not an annual.
Sow indoors at any time of year.
Soak the seeds in a container of warm water for a couple of hours. Place 2 or 3 seeds in 7cm (3”) pots of seed compost, giving enough water to make the mixture barely moist. Cover the pot with clear plastic wrap.
Place the pots in bright light at a temperature of 18 to 21°C (65 to 70°F).
Water enough to keep soil from drying out completely. Germination will vary, from a few days to several weeks as it is dependent on the temperature.
Remove the plastic cover once they have germinated. The seedling leaves will not move. About three weeks later, real leaves will appear and will move.
Choose the strongest seedling and transplant the weaker ones to other pots. Once they are well established, the plants should be transplanted to 13cm (5”) pots of standard soil-based potting mixture.
Mimosa pudica is very easy to grow from seed and is a very adaptable plant but it does need humidity and warmth. It can be kept in most situations in a warm greenhouse or in the house. Keep a mister close by and mist it with tepid water occasionally. It needs light; it is shade intolerant: in the wild, it does not compete with tall vegetation.
Being a member of the pea family, Leguminosae, it has the ability to fix nitrogen from the air and is therefore adaptable to most soil types, including those of poor quality.
The plant flowers best and its foliage is at its most attractive when the roots are confined in a relatively small space, however, root ends appearing through the drainage holes will indicate that repotting is necessary. Repot using a soil-based potting mixture when the roots have filled the current pot.
If it becomes “leggy” cut it back, it will then send up new shoots.
Indoor, Greenhouse or conservatory plant, Children.
The scientific name is derived from the Greek, Mimosa meaning 'a mimic' which alludes to the sensitivity of the leaves; and the Latin pudica, meaning bashful, retiring or shrinking.
A similar but unrelated plant, Acacia dealbata, is sold as mimosa by florists.
- Additional Information
Packet Size 500mg Average Seed Count 70 Seeds Family Leguminosae Genus Mimosa Species pudica Common Name Touch-me-not Other Common Names Humble plant, Shame plant, Sleeping grass Flowers Mid Summer to Early Autumn Foliage Fern-like, Mid Green Height 45-60 cm (18-24 in.) Position Indoors in temperate zones Notes Hardy above 5°C (41°F)