Ferocactus pilosus
Light: Full sun to light shade. In Phoenix, acclimate gradually to strong sun; young or nursery-grown plants benefit from afternoon shade.
Water: Low water; water deeply but infrequently during warm weather, allowing soil to dry completely between waterings. Keep nearly dry in winter and avoid watering saturated soil during monsoon periods.
Soil: Excellent drainage is essential; use gritty, mineral-rich cactus soil or a raised planting mound. Tolerates alkaline soil but not persistently wet clay.
Mature size: Typically 4–8 feet tall and 18–30 inches wide per stem; very old specimens may reach 10 feet, and clumps can spread wider.
Bloom: Usually spring through summer on mature plants; flowering may take many years from seed.
Evergreen / deciduous: Evergreen; leafless, with green photosynthetic stems.
Growth rate: Slow.