Fairy Castle Cacti are slow-growing cacti, but they can reach up to six feet in height at maturity. Each stem has five sides and is lined with white, wooly spines along each ridge. The stems are vibrant green in color but will brown with time in a process called corking.
Over time, Fairy Castle Cacti produce branches, which has led to their turreted castle image.
As with most Cereus, the Fairy Castle Cactus is a night-blooming cactus. The flowers are large and either white or yellow in color. This cactus rarely blooms, and most individuals won’t bloom until they are at least ten years old.