It is a very slow growing plant that will eventually reach 6 feet tall. The stems on the fairy castle cactus plant are five-sided with wooly based spines along each plane. The limbs are a bright green turning woody and brown with age. Different branches are formed over time which slowly lengthens and produce an interesting silhouette. The fairy castle cactus rarely blooms. Cacti need perfect growing conditions to produce flowers and the plants in the Cereus family bloom at night. Fairy castle cactus flowers are large and white and usually will not occur until the plant is ten years old or more. If your cactus comes with a flower, examine it carefully. It is likely a fake bloom used as a marketing ploy. There is no need to remove the fake fairy castle cactus flower, as it will fall off by itself eventually.