Old Man Cactus, Old Man of Mexico, Cabeza de Viejo

Frost Tolerance: Hardy to 14°F (-10°C) for short periods

Heat Tolerance: Prefers some afternoon shade in the low deserts

Sun Exposure: Full sun

Origin: Mexico (Hidalgo, Guanajuato)

Growth Habits: Slow growing to a large column, seldom ramified, 45 feet tall (11 m) by 18 inches (45 cm) in diameter; 12 to 30 ribs; 1 to 5 central spines, up to 2 inches long (5 cm); 20 to 30 hair-like laterals.

Watering Needs: Little to moderate water in summer, almost none in winter, very rot prone particularly when young, needs good drainage

Propagation: Seeds, cuttings

Cephalocereus senilis at the DBG

Most of the species from the Cephalocereus genus have been moved to Pilosocereus.

Blooming Habits:
The pseudocephalium starts on the side of the stems when they reach 20 feet (6 m). The woolly hair can reach 8 inches or more (20 cm). Eventually the pseudocephalium will cover the top of the stem.
The 2-inch long whitish pink flowers (5 cm), open at night in April. They are followed by pinkish-red fruit, 0.8 to 1.2 inches long (2-3 cm) covered with yellowish hair.

Culture:
In nature, the Cephalocereus reaches 2 feet tall in 20 years, it can be much faster with proper watering and fertilizing. To keep the cactus smaller, the top can be cut in spring, dried for 3 days, and replanted. It is possible to wash the white "hair" with diluted shampoo to keep it white.