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Acanthocereus tetragonus: The Fairy Castle Cactus

Acanthocereus tetragonus is a species of cactus that is native to various regions of the Americas, from Florida and Texas to Mexico and South America. It is also known as the night-blooming cereus, barbed-wire cactus, sword-pear, dildo cactus, triangle cactus, and Órgano-alado de pitaya. One of its cultivars, the Fairy Castle Cactus, is a popular houseplant for its miniature size and castle-like shape.

Description

Acanthocereus tetragonus is a tall, columnar cactus that can reach a height of 2–7 m (6.6–23.0 ft). It has dark green stems with three to five angles and grey areoles with spines. The flowers are large, white, and fragrant, and open only at night. The fruits are red, sweet, and edible.

The Fairy Castle Cactus is a dwarf cultivar of Acanthocereus tetragonus that grows slowly and has many curved branches that resemble the turrets of a castle. It rarely blooms or produces fruits.

Cultivation

Acanthocereus tetragonus is a hardy and drought-tolerant cactus that thrives in full sun, well-draining soil, and warm to hot temperatures. It can be grown outdoors in desert, tropical, or xeriscape gardens, or indoors in pots with adequate light and ventilation. It needs minimal watering and fertilizing, and can be propagated by stem cuttings.

The Fairy Castle Cactus is an ideal succulent for beginners, as it requires very little care and can adapt to various conditions. It can be grown indoors in bright but indirect light, or outdoors in partial shade. It needs water only when the soil is completely dry, and a diluted cactus fertilizer once or twice a year. It can be pruned to maintain its shape and size.

Uses

Acanthocereus tetragonus has various uses besides being an ornamental plant. The young stems can be eaten as a vegetable either raw or cooked, while the fruits can be consumed fresh or made into jams or juices. The spines can be used as needles or fishhooks, and the stems can be used as fences or firewood.

The Fairy Castle Cactus has no known uses other than being a charming decoration for any home or office.

Interesting Facts

Here are some interesting facts about Acanthocereus tetragonus and its Fairy Castle Cactus cultivar:

• The flowers of Acanthocereus tetragonus are pollinated by hummingbird moths, which are attracted by their scent and nectar.
• The Fairy Castle Cactus is sometimes confused with another cactus cultivar, the Cereus hildmannianus ‘Fairy Castle’, which has more spines and fewer branches.
• Acanthocereus tetragonus is one of the few cacti that can grow in salty soils and tolerate salt spray.
• The Fairy Castle Cactus can live for decades if given proper care and conditions.
• Acanthocereus tetragonus is also called the Barbed-wire Cactus because its spines can cause painful wounds if touched.

Care Tips

If you want to grow Acanthocereus tetragonus or its Fairy Castle Cactus cultivar, here are some care tips to follow:

1. Choose a pot that has drainage holes and is slightly larger than the cactus. Use a well-draining cactus mix or make your own by combining equal parts of sand, perlite, and potting soil.
2. Place the cactus in a sunny spot that receives at least six hours of direct sunlight per day. If you grow it indoors, you may need to supplement it with artificial light during the winter months.
3. Water the cactus sparingly and only when the soil is completely dry. Avoid overwatering or underwatering, as both can cause root rot or dehydration. Water less frequently in winter when the cactus is dormant.
4. Feed the cactus with a diluted cactus fertilizer once or twice a year during the growing season. Do not fertilize in winter when the cactus is resting.
5. Repot the cactus every two to three years or when it outgrows its pot. Use fresh soil and a slightly larger pot. Be careful when handling the cactus, as its spines can be sharp and irritating.

Pests and Problems

Acanthocereus tetragonus and its Fairy Castle Cactus cultivar are generally resistant to pests and diseases, but they may still encounter some problems if not cared for properly. Here are some common pests and problems that may affect these cacti:

• Mealybugs and scale insects are tiny bugs that suck the sap from the cactus and leave behind white cottony masses or brown scaly patches. They can be removed by wiping them off with a cotton swab dipped in alcohol or spraying them with insecticidal soap.
• Spider mites are microscopic mites that feed on the cactus and cause yellow spots or webbing on the stems. They can be controlled by increasing the humidity around the cactus or spraying it with a miticide.
• Fungal infections are caused by excess moisture or poor ventilation. They can result in black spots, soft rot, or white mold on the cactus. They can be prevented by watering less frequently, improving air circulation, and removing any infected parts.
• Sunburn is caused by exposing the cactus to too much direct sunlight or sudden changes in temperature. It can cause brown or white patches on the stems. It can be avoided by acclimating the cactus gradually to more sunlight or moving it to a shadier spot.
• Stem rot is caused by overwatering or physical damage to the cactus. It can cause the stems to turn mushy and black. It can be treated by cutting off any rotten parts and letting the wound heal before repotting.