Mimosa nuttallii Pink Sparkles

The Mimosa nuttallii Pink Sparkles is a hardier variety of the Mimosa pudica, which can now be more easily grown in open ground. This undershrub is cultivated for its globular flowering in pale pink and for its more imposing stature than that of the Mimosa pudica, it has retained its ability to react to the slightest stimuli by quickly retracting its leaflets.

The Mimosa nuttallii Pink Sparkles, known by the names of Sensitive or Humble Mimosa, forms a well-erected stem with a woody base that can become creeping as the plant ages. It is branching and produces a large number of spinules (small thorns). It flowers generously from June to September producing a profusion of flowers assembled in corymbs 3 to 4 cm (1.2 to 1.6 in) in diameter, very globular. The anthers, like white dots at the top of the many stamens, give the flower a fluffy appearance.

It is the leafing that makes this tropical plant so curious. The evergreen foliage is composed of pinnate leaves containing 11 to 25 very excitable leaflets. The slightest stimulus, vibratory or heat, generates in this plant an extraordinary phenomenon rarely encountered in the plant world. Depending on the intensity of the stimulation, it retracts one, several leaflets or even the entire leaf at a speed of 2 m (6 ft 7 in) per minute. The movements of plants (growth – flowering –, circadian movements – etc.) are generally invisible to the naked eye. They could be explained by a pressure differential in the cells at the leaflets' base. This process is, it seems, an effective defence strategy aimed at scaring off herbivores or dislodging unwanted insects.

The Mimosa nuttallii Pink Sparkles is a half-shade plant. It can grow under the shelter of taller plants and benefit from their shade while having partial access to light. It particularly likes rather acidic soils. Weakened as soon as temperatures reach 5°C (41 °F), it is usually grown in pots.