Acanthocereus Tetragonus [a-kaen-tha-sear-as, tet-ra-gau-nus] is a popular species of cactus.
Formerly known as Cereus tetragonus, the cactus is native to Florida and the Lower Rio Grande Valley of Texas in the United States.
The cactus plant also originates in popular regions of Mexico, the Caribbean, Central America, and northern South America.
The spiky plant shares resemblance with the turrets of a castle due to its curvy, columnar shape.
This is the reason why it is popularly known as a fairy castle cactus.
Some experts categorize this famous cactus as a cultivated variety of Cereus hildmannianus.
Fairy castle cactus is either in the subspecies uruguayanus or monstrose.
Aside from the fairy castle cactus and its scientific name, the plant goes by many other common names as follows:
- Barbed Wire Cactus
- Triangle Cactus
- Night-blooming Cereus
- Sword Pear
Fairy Castle Cactus Care
Size and Growth
Acanthocereus Tetragonus is a slow-growing succulent, tall and spiky, boasting a height of 6′ to 23′ feet.
It features dark green stems up to 8″ inches taller and grey areoles up to 1″ inch long.
On each stem, there are five sides with short white spines growing along the ribs.
The areoles of the plant come with one or two spires, white/yellow in color and 1.5″ inch in length.
Since Acanthocereus cacti enjoy the full sun, they grow best in warmer climatic regions.
Flowering and Fragrance
The pointy cactus rarely blooms but when it does, it produces large, white flowers.
These blooms are usually 3″ – 6″ inches long and 5.5″ – 8″ inches wide.
The plant takes 10 years (or more) to mature and develop flowers.
If the cactus is already full of blooms, observe it carefully as they may be fake flowers.
The cactus flowers consist of two main parts – outer tepals and inner tepals.
The outer tepals are light green while the inner tepals are simply white.
The pistils are creamy white.
The yellow flowers open up at midnight and stay abloom till dawn.
Along with flowers, the vivid red fruits are a sight to behold.
Lighting and Temperature
These succulent plants enjoy the full sun plant and grow best in a bright sunny location, far away from rainfall or air conditioning.
This slow-growing plant is categorized in USDA hardiness zones 10a to 11b.
These include areas with climatic temperatures from 25° to 50° degrees Fahrenheit (-4° to 10° C).
Watering and Feeding
Being a succulent, fairy castle cactus has typical succulent water requirements.
When watering, the liquid must come out of the drainage hole and allow the soil to completely dry before watering again.
Overwatering is the most common way to destroy fairy castle cacti.
In winters, watering is cut down to half the amount it receives in summers.
For feeding, a fairy castle cactus responds to cactus fertilizers, specifically designed for their needs.
Apply a cactus fertilizer in Spring when growth resumes and every month in the summer season at half strength.
Avoid feeding the plant in winter.
Soil and Transplanting
Acanthocereus Tetragonus ‘Fairy Castle’ flourishes in a well-drained soil or cactus potting soil.
To make a DIY potting soil, combine houseplant potting soil, sand and perlite together. This results in a grainy medium for the cactus.
Ideally, fairy castle should be transplanted when it outgrows the space it is in.
The plant needs a lot of space for root development. Hence, repotting should be done every other year or when the plant has outgrown its pot.
Grooming and Maintenance
This low-maintenance plant is super easy to look after and why it’s a top pick for amateurs or beginners.
Always plant the cactus in a clay pot.
An unglazed clay pot is a great option as it evaporates the unnecessary excess moisture. It is a great option for those looking for a columnar cactus.
Place the plant where enough sunlight is present.
During winters, bring the plant indoors (it makes an excellent cactus window sill plant) as the exposure to cold temperatures may damage the plant for good.
How To Propagate Acanthocereus Tetragonus
Fairy castle cacti propagate from cuttings.
For this, cut a branch as long as the length of a hand and replant it in damp, well-drained miracle soil.
This type of soil helps to harden and dry out the cutting, allowing roots to develop.
Acanthocereus Tetragonus Pests and Diseases
The green finger plant isn’t susceptible to any serious diseases or pest problems.
However, overwatering causes bacterial or fungal diseases.
Less common pests are fungus gnats and spider mites.
Learn more about spider mites on succulents and more.
Fairy Castle Cactus Suggested Uses
Having succulents and cacti like fairytale castle help keep the air fresh in homes.
Plus, they help elevate indoor beauty with their unique, exotic appearance.
This makes them the best indoor cacti but also a great addition to fairy gardens.