Old Man Cactus is native to Mexico. Because many natural habitats have been destroyed by collectors, its export is prohibited by the Mexican government. The long columnaris usually unbranched and, in its native land, this can attain a height of 15 m (49 ft) and a diameter of about 40 cm (16 in). The 20-30, not very high, longitudinal ribs are green at first, later grey. The areoles are rimmed with 20-30 delicate white spines which may be up to 12 cm (5 in) long. The central spines are only 2-5 cm ( ¾-2 inch) long. Flowers are produced only by mature plants that have attained a height of about 6 m (20 ft). Coloured pale pink, they are usually 5 cm (2 inch) long and 7.5 cm (3 in) across. They emerge from a rufous-brown cephalium – a special formation of clustered areoles, wavy wool and bristles developed on top of the stem, and open at night.
Growing C. senilis is relatively easy. Its only requirements are plenty of light and warmth. It is usually propagated from, sown in heavy clay at a temperature of 10°-15°C (50°-59° F).