Mimosa - Sensitive Plant
DESCRIPTION: This is a shrubby plant from Brazil, India and Equador that belongs to the Pea family, Leguminosae. There are numerous kinds, but only a few are in cultivation in North America. This plant has prickly stems and finely divided leaves. Its flowers are produced in little fluffy balls that are usually pink or purple. These plants are known as the Sensitive Plant because its leaflets fold up when they're touched or blown by the wind. They close up in pairs beginning at the top until they reach the base of the leafstalk, when the whole leaf drops as if it's on a hinge.
POTTING: M. pudica is best treated as an annual. A compost of equal parts loam, peat, leaf mold and sand is used. When you repot, the balls of soil must be kept undisturbed. After repotting, they should be shaded and kept in a humid atmosphere. No water is applied to the soil until it becomes fairly dry, then it's saturated and kept moist throughout the summer. When they're established in 4-inch pots, they should be kept in a well-ventilated sunny greenhouse for the remainder of the summer; afterwards they are thrown out, because they are not easy to keep alive during the winter. Most failures with the cultivation of Mimosas are due to overwatering. It will cause the roots to decay quickly. M. speggazzinii forms a low shrub that can be kept for many years. It's raised and treated the same way M. pudica is, except it can be lifted in the fall and kept in a greenhouse instead of being discarded. The minimum temperature should be 55 degrees and the soil should become fairly dry before watering. In early March, the shoots should be cut back by one-half and frequently sprayed with water until side growth appears. They are then repotted in pots one size larger, and afterwards treated the same as seedlings.
PROPAGATION: M. pudica is propagated best with seeds that are sown in March in a compost of equal parts of peat moss and sand, or in sandy soil. Two-inch pots are used; these should be half-filled with crocks, which are then covered with a small amount of rough leaves or fiber. Fill the pots up with the compost and plant three seeds in each pot. After the soil is moistened, the pots are packed close together in a box on a layer of damp moss. Cover the box with a pane of glass and set in a greenhouse with a minimum temperature of 55 degrees. M. speggazzinii and other perennials can also be increased with cuttings taken in the spring. The side shoots, with a "heel" ( a piece of the old branch still attached), can be taken when they're 2 inches long. Remove some of the lower leaves and smooth the "heel" with a sharp knife. Insert the cuttings in a propagating case having a bottom heat of 75 degrees. When they've formed roots, pot and treat them as advised for seedlings.
VARIETIES: M. speggazzinii; M. pudica; M. sensitiva; M. ruicaulis.
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