Mammillaria plumosa aka Feather Cactus

Mammillaria plumosa is a slow-growing cactus that forms dense clustering mounds. Individual stems reach about 4-7 cm in diameter and 7-12 cm in height, while mature clusters typically spread to about 40 cm wide. It takes 5-10 years to reach its full size, though clusters can eventually exceed 1 meter in width over many years with proper care.

Mammillaria plumosa thrives in warm temperatures between 65-75°F (18-24°C) during the growing season. It is moderately frost tolerant and can survive brief exposure to temperatures as low as 20°F (-6.7°C), making it hardy in USDA zones 9-11. A cool winter rest period around 50°F (10°C) encourages better flowering but avoid prolonged freezing temperatures.

Mammillaria plumosa produces charming ring-shaped clusters of small flowers at the stem tops in late summer to autumn. The daisy-like blooms are typically creamy white, greenish-yellow, or occasionally dull pink with darker midstripes, measuring about 1.5 cm across. The flowers emit a sweet fragrance and attract pollinators. To encourage flowering, provide a cool, dry winter rest period.

Yes, Mammillaria plumosa produces sweetly scented flowers. The fragrance is most noticeable during blooming in late summer and autumn. The pleasant scent attracts bees, butterflies, and other pollinators to the small cream-colored to pink flowers.

Mammillaria plumosa propagates easily from offsets (pups) that form around the base of mature plants. Wait until offsets are at least one-third the size of the mother plant, then carefully separate them with a sterile knife. Seeds can also be sown at 66-75°F (19-24°C) in early spring, though this method is slower.

Repot Mammillaria plumosa sparingly, typically every 2-3 years or when it outgrows its container. This slow-growing cactus doesn't require frequent repotting. When you do repot, use a slightly larger pot with fresh, well-draining cactus mix. Repot in spring at the start of the growing season, and allow the plant to settle for a week before watering.

Mammillaria plumosa can grow outdoors in USDA hardiness zones 9-11, where temperatures stay above 20°F (-6.7°C). Plant in full sun with excellent drainage, amending native soil with coarse sand and gravel. In its native Mexico, it grows on limestone cliffs at elevations of 730-1,350 meters. Protect from excessive rain and provide afternoon shade in extremely hot climates.

The most common problems are mealybugs and root rot. Mealybugs can hide beneath the dense white spines, making them hard to detect—some growers apply preventative systemic insecticide annually. Root rot results from overwatering; signs include a soft, mushy base or yellowing stems. Provide excellent drainage, bright light, and good air circulation to prevent both issues. Treat mealybugs with rubbing alcohol or insecticidal soap.

The feathery white spines of Mammillaria plumosa can become dusty over time. Use a soft brush or can of compressed air to gently remove dust from between the spines. Avoid getting water on the spines when watering, as this can cause staining and diminish their white appearance. Handle carefully as sharp spines hide beneath the soft-looking exterior.

Mammillaria plumosa var. roseiflora is a recognized variety with pink-tinged flowers instead of the typical cream-white blooms. The main species has been classified under several names historically, including Chilita plumosa, Ebnerella plumosa, and Neomammillaria plumosa, but these are now considered synonyms of the accepted name Mammillaria plumosa.