Cereus tetragonus is native to America. It is a slow-growing plant that will eventually reach 6 feet tall. Some expert classify the cactus as a form of Acanthocereus tetragonus. It has also been given the species name in Cereus genus.
The stems on 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 lengthen 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.
In the growing season, the plants should be watered at least once a week. When watering, the soil should be given a good soaking, allowing excess water to drain away. Allow the compost to dry out slightly between each watering.
Needs a lot of sunlight, but it has to be protected from the strongest rays of the sun. In a south-facing window, blinds should be shading it form direct light. An east facing window, where the sun disappears after about 10 AM, is a good choice as is a west facing window where the plant will receive afternoon sun.
Cacti require a porous, sandy or pebbly potting soil that provides plenty of aeration and excellent drainage. A good cactus potting mixture will also consist of some organic material that makes moisture available to the plant roots when watered but then dries out quickly.
Cacti fertilizer requirements are pretty simple. Any good houseplant food (diluted to half) that's higher in phosphorus than nitrogen is a good choice. A 5-10-5 solution can work well.
Trim out dead and damaged leaves any time, pinching off or cutting off each of those leaves at its base. Avoid cutting into a plant's main stems or its crown, which is where its leaves and roots meet.
“Fairy Castle Cactus” is not cold hardy, so if you live in a zone that gets colder than 30° F (-1.1° C), it's best to plant this succulent in a container that can be brought indoors. Average room temperatures will suffice.
Many seasoned gardeners recommend using a container that is about 10% larger in diameter than the cactus plant at its widest point.