Mammillaria spp.
Light: Bright light with morning sun and afternoon shade in Phoenix; protect from intense western sun and reflected heat. Acclimate gradually to direct sun.
Water: Low water; water thoroughly, then let soil dry completely. Reduce watering sharply in winter and during heat-related dormancy; never leave pots standing in water.
Soil: Very well-drained, gritty cactus mix with abundant pumice or coarse mineral material. Use containers with drainage holes or raised, rocky planting areas.
Mature size: Many common species reach 2–12 inches tall and 3–8 inches wide per stem; clustering species can form patches 1–2 feet wide. Some species grow larger.
Bloom: Usually late winter through spring, sometimes into summer; timing and repeat flowering vary by species.
Evergreen / deciduous: Evergreen succulent cactus.
Growth rate: Slow to moderate, depending on species and growing conditions.