Mammillaria compressa aka Mother Of Hundreds

Mammillaria compressa is a perennial cactus in the Cactaceae family. Common names include mother of hundreds and compressed pincushion cactus. It comes from eastern and central Mexico, reaching west to Jalisco. It grows in dry scrub and desert habitats. Plants start with one stem, then form broad clumps. The species remains widespread, with a reported Least Concern status. Collection for sale affects some wild groups.

Garden plants reach about 1.6 feet [0.5 m] tall and wide. Larger clumps can spread to 3.3 feet [1 m]. Individual stems reach about 0.7–0.8 feet [0.2–0.25 m] tall. They can grow 0.33 feet [0.1 m] across. Their shape ranges from club-like to cylindrical. The blue-grey-green stems contain latex and bear close-set, firm tubercles. White wool and bristles grow in the gaps between them. Spines range from pale brown to chalk-white with brown tips. Central spines are often absent.

Small, bell-shaped flowers form a ring near each stem's crown. Their colour ranges from purple-pink to deep red. Sources place flowering in winter and spring. Red, club-shaped fruit follows, with brown seeds inside. People gather the fruit from wild plants for food. They eat it raw. Useful Tropical Plants records no known hazards or medicinal uses. This does not establish safety for pets or every plant part.

Give this cactus strong light, with shade from hot sun. Use a porous cactus mix that drains well. It accepts sandy or loamy soil across a broad pH range. Water during active growth, but avoid soil that stays wet. Reduce watering in winter and keep good airflow around plants. Damp pots can cause root loss. Too much water and shade can also distort growth. RHS rates it H2, so frost-free shelter is the safer approach. Other sources report brief frost tolerance when plants stay dry. LLIFLE reports about 23°F [-5°C], with lower figures less certain.

This cactus suits pots, patios, greenhouses, conservatories, and indoor growing. Its offsets can fill a broad pot within a few years. It grows fast compared with many other Mammillaria species. RHS gives five to ten years to reach full size. No pruning is needed. Grow new plants from seed or remove offsets in early spring. Mealybugs may attack stems, and root mealybugs may infest pots. RHS reports few disease problems, though wet roots remain a concern.