Old Man Cactus Cephalocereus senilis

Old Man Cactus is a tall, columnar succulent in the cactus family with spines that form fine white hairs reminiscent of an old man.  It is native to Northeastern Mexico but becoming more challenging to find in its natural habitat, but widespread propagation and popularity in cultivation may reduce the demand on wild populations. Old Man Cactus has clusters of stems that may grow to16 to 50 feet tall. However, the most striking feature is the shaggy coat of long, white hairs, hence the common name old man cactus. The coat is particularly striking on the young cactus, but, as the plant ages, the stem loses its covering. The hairs are modified spines and serve to protect the plant from frost and sun by reflecting the rays of the sun and insulating the cactus from heat and cold.  The hairs are only the radial spines of the cactus; beneath them are sharp yellow central spines. The solitary, nocturnal flowers are red, yellow, or white, though the plant may not flower for 10 or 20 years.  

Old Man Cactus is a popular houseplant, grown for its woolly appearance. It prefers a fertile, well-drained soil mix and bright sunlight, which encourages growth of the hair. Water the plants well and allow them to dry before watering again. Using an unglazed pot for your indoor planting, which will allow excess moisture to evaporate. During the growing season, fertilize it monthly with a balanced fertilizer. If kept well-fed and watered throughout the warmest months, and acclimated to full sun, it can produce 7 inches of growth every year. If grown outside, place it in full sun; if inside provide bright light and some direct sun. During the winter, withhold water and fertilizer.

When moving a houseplant from the house to the outdoors, too much light too soon can cause the plant to become sunburned.  Place outdoors for a brief period of time, gradually increasing the sun exposure over a period of several weeks.  This will allow the plant to adjust to the increased sunlight.

Growing to heights of 50 feet in the wild, when grown as a houseplant it will typically reach a maximum height of 3-4 feet tall.  It can take upwards of 200 years for this plant to reach it full height when situated in its natural habitat.  

Diseases, Insect Pests, and Other Plant Problems:  Mealybugs, scale and other flying insects can be an issue as they are difficult to view due to the hairs present on the plant.

Susceptible to fungal diseases if overwatered. If kept damp through cold periods, they will suffer.