The Powder Puff Mimosa, Mimosa strigillosa, is a low-maintenance and visually interesting groundcover. Its delicate, fern-like foliage creates a soft texture, and its fluffy, pink-purple flowers add unique charm. This species is also noted for its characteristic leaf movement, where foliage folds upon touch or at night. Once established, it is drought tolerant, making it a sustainable choice for various landscapes.
Understanding Powder Puff Mimosa
Mimosa strigillosa, also known as Powder Puff Mimosa, Sunshine Mimosa, or Sensitive Plant, belongs to the Fabaceae family. This native perennial is found throughout the southeastern United States, often in disturbed areas and roadsides. It typically grows as a mat-forming groundcover, spreading by rooting stems and rhizomes, and can reach up to 8 inches in height.
Its bipinnately compound leaves feature numerous small leaflets. Their sensitivity to touch causes leaflets to fold rapidly, a phenomenon known as nyctinastic movement. From spring through summer, it produces showy, spherical pink-to-lavender flowers, approximately one inch across, with protruding yellow-tipped stamens. These flowers develop into small, flattened, oblong seed pods.
Planting and Growing Conditions
Powder Puff Mimosa thrives in full sun but tolerates partial shade. In shadier conditions, leaves may appear larger, while full sun encourages smaller foliage.
Well-draining, sandy or loamy soil is preferred. It adapts to various soil types but performs best within a pH range of 6.2 to 7.1. Acidic soils below pH 4.1 are unsuitable. A soil analysis before planting can help determine if phosphorus and potassium amendments are needed.
Planting can occur in spring or early fall. When planting from seed, scarification significantly improves germination rates; unscarified seeds may take up to a year, while scarified seeds can germinate within 5 to 10 days. Seeds should be planted about 1/4 inch deep.
For nursery starts, plant them 2 to 4 feet apart. New plants require consistent watering (1-3 times weekly) for the first few months of establishment. Suitable for USDA Zones 8-11, it withstands temperatures down to about 15°F (-9°C), though top growth may die back in cooler regions.
Ongoing Care
As a legume capable of nitrogen fixation, the plant produces its own nitrogen. Therefore, additional nitrogen fertilization is generally not needed and can encourage weed competition. If soil tests indicate deficiencies, phosphorus and potassium can be applied to established plants. A low-phosphorus, controlled-release fertilizer can be used if yellowing occurs before nodulation is fully established.
Pruning controls spread, maintains shape, or encourages denser growth. Since stems root at their nodes as they spread, edging or barriers manage its expansive nature. It tolerates mowing, making it a suitable turfgrass alternative. Deadheading spent blooms is unnecessary, as flowers are self-cleaning and give way to small seed pods.
Propagation
Powder Puff Mimosa propagates through seeds and cuttings. Seed propagation is common, but the hard seed coat requires scarification for optimal germination. Scarification can be done mechanically by nicking or lightly rubbing the seed coat with sandpaper. Soaking seeds for 24 hours before planting also softens the seed coat. After scarification, sow seeds in well-draining soil and keep moist until germination.
Cuttings are also effective for propagation. Herbaceous stem cuttings can be placed in water or directly into potting soil to root. Cuttings showing signs of rooting at their nodes are particularly successful. Its natural ability to spread via rooting rhizomes and stolons allows for self-propagation, forming dense mats over time.
Common Issues
Powder Puff Mimosa is generally robust with few major pest or disease problems. Overwatering or poor drainage can lead to root rot. Ensuring well-draining soil and appropriate watering prevents this problem.
Insufficient light can cause leggy or less dense growth. Occasionally, spider mites or mealybugs might appear, but infestations are typically not severe. Maintaining good air circulation and plant health generally deters such pests.