How cool is this plant? Sensitive plant (Mimosa pudica, Zones 9-11) from South America is known for curling up its leaves when touched. The leaves uncurl about 30 minutes later. This helps the plant protect itself from being eaten. Leaves also curl up at night. The reaction isn't always the same either - the plants will stop closing their leaves as much if they learn the disturbance will not harm them. - Diana Koehm, Assistant Editor Fine Gardening editors talked about sensitive plant in our pod