Acanthocereus tetragonus (Fairy Castle Cactus)

Acanthocereus Tetragonus (Fairy Castle Cactus)

As a part of the Cactaceae family, Acanthocereus tetragonus is an exciting addition to your cacti collection. It is also known as the Fairy Castle cactus thanks to its multiple branches that are curved to give the appearance of the towers and minarets of a fairytale castle. The other common names of the cactus are Triangle cactus, Sword-pear, or wire cactus.

The good part is that this cactus variety is pretty common. You can get the Acanthocereus tetragonus for sale from almost all online cactus stores. There is only one known type of fairy castle cactus.

Acanthocereus tetragonus (Fairy Castle Cactus)

Physical Characteristics

Cactus Acanthocereus tetragonus is a columnar cactus belonging to Mexico, Florida, and the Texan Rio Grande Valley. It grows quite tall, almost 2 meters to 7 meters in height. The plant is characterized by green stems and gray areoles. The central areoles are filled with 1-2 spines. The radial areoles have about 6-8 spines. 

Fairy Castle Cactus Flower

The flowers of the Acanthocereus tetragonus open at night and close when the sun comes out. As a result, the flowers attract moths. The typical fairy castle cactus bloom has greenish-white outer tepals and pure white inner tepals. The pistil is creamy white. The flowers are pretty and colorful. The center is a deep reddish-orange. 

Fairy Castle Cactus Care  

This is a drought-resistant cactus that is great for beginners. The slow-growing cactus does not need much care. However, you should pay attention to the following conditions:

1. Fairy Castle Cactus Watering

The watering needs of the cactus is typical to the Cactaceae family. It does not need much water and neither does it need regular watering. However, being a plant, it does need some amount of watering. More water is required during the dry summer season and less during winter. Between two rounds of watering, ensure that the soil is completely dry. Soggy soil or water standing at the root can cause parasitic or mealybug growth. This will cause the cactus to perish faster than you realize.

2. Fairy Castle Cactus Light Requirements

Like most of its family members, the fairy tale cactus needs full sun to thrive. In other words, this is a full-sun cactus. In case the cactus is not exposed to plentiful sunlight, the color of the stems will start to fade – you will find them turning yellow. Another sign of poor exposure to the sun is that the stems will start to misshapen.  This does not mean that it will have stunted growth indoors.  The cactus has healthy growth in partial shade too.

3. Temperature

The cactus needs hot temperature conditions for the best growth. It is sensitive to frost and if the outdoor temperature falls below 32°F, it is best to take the plant indoors. Ensure that the cactus is away from the vents of the air-conditioner because it can have a damaging effect on the cactus.

4. Soil Requirements

It is important that the soil is well-draining. Mix the standard soil with sand or perlite, bark, gravel, etc., to make the soil more porous. One of the other things to take care of, especially fairy castle cactus indoor care should involve the use of pots with enough drainage holes. Unglazed pots like terra cotta pots are the best to go ahead with.

5. Fertilizers

Fertilizers can be added to the soil during the growing season. However, it is not advised during the dormant season, i.e., the winter season. You can fertilize the cactus during the spring season.

Acanthocereus tetragonus (Fairy Castle Cactus)

Fairy Castle Cactus Repotting

It is an excellent practice to repot the cactus once each year. This is because the cactus roots grow in all directions and need enough space for proper growth. Make sure that the new pot is 1 to 2 inches bigger than the potting mix. You need to use tongs or gloves to protect yourself from spines when repotting.

Propagation of the Acanthocereus Cactus

The best way to propagate the fairy cactus is via seeds or stem cuttings. Propagating fairy castle cactus has a higher success rate with stem cuttings. 

Fairy castle cactus cutting propagation method: First sterilize a sharp pair of gardening scissors or a knife. You need to cut a single stem from the parent plant. Let that stem be callous for a few days. Then, the plant is in a well-drained sandy loam soil. Follow the watering pattern mentioned above. 

Seed propagation of fairy castle cactus: The fruits of the cactus bear seeds. These can be sowed in a cactus potting mix. Fairy castle cactus seeds propagation is a prolonged process. It is advisable to plant the seeds outdoors only if you live in warmer areas - a 9A zone or above. Else, if you are a resident of a colder region, it is best to plant the fairy castle cactus indoors.


  1. How can the Acanthocereus tetragonus be used?

Since the fairy castle cactus with or without flowers looks amazing, one of its topmost uses is for ornamental reasons. If you have a garden outdoors, this cactus species can make the place look aesthetically graceful. You can also plant the cactus as a fence with its spines protecting your backyard. The cactus is consumed as a vegetable in its native place. It can be directly consumed or cooked and then eaten. The fruits of the cactus tetragonus are edible with a sweet taste.

You can bring it indoors too, especially the miniature variety. It makes for a good addition as a houseplant in your living room or terrace garden.

  1. Is it easy for this cactus to bear flowers?

In most cases, the Acanthocereus tetragonus flower does not appear for a long time. In other words, it takes time for the plant to bear flowers. But once it does, the charming white flowers can take your breath away.

  1. How does the cactus get its name?

The Acanthocereus tetragonus fairy castle cactus gets its name from the Greek word Akantha. It means ‘thorny.’ The fact that the cactus has a thick growth of spines led the discoverers to name it Acanthto. 

  1. Why is my fairy castle cactus yellow?

Though cacti are drought-resistant, if your fairytale castle cactus is turning yellow, it can mean three things – it is being watered too often or water is not draining off as well as it should; it is not getting sunlight, or it has been attacked by parasites.

  1. Where can I buy fairy castle cactus for sale?

Acanthocereus tetragonus can be ordered from online cactus and succulent stores like Planet Desert.  Ensure that you get the fairy cactus for sale from the best store online so that it arrives in the right condition.

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