Acanthocereus Tetragonus 'Monstrose'

Common Names: Fairy Castle Cactus, Barbed Wire Cactus, Triangle Cactus

Appearance

A columnar, slow-growing cactus with multiple branching stems that grow in a clustered, castle-like formation.

Stems are deep green with five distinct ridges lined with small clusters of short, white spines.

Can grow up to 6 feet (1.8 meters) tall over time, though growth is slow.

Care & Growing Conditions

Light: Prefers full sun to partial shade; too little light can cause elongation.

Soil: Well-draining, sandy, or cactus mix soil.

Watering: Drought-tolerant; water moderately and allow soil to dry completely between waterings.

Temperature: Thrives in USDA zones 9-11; not frost-hardy and should be kept above 30°F (-1°C).

Humidity: Prefers dry conditions and does not tolerate high humidity well.

Flower

Rarely blooms in cultivation; when it does, it produces large, white, nocturnal flowers.

Blooms appear in late spring to summer, usually on mature plants.

Toxicity

Non-toxic to humans and pets, but spines can cause irritation if touched.

 Special Notes

The Monstrose form is a mutation of Acanthocereus tetragonus, which gives it its unique, contorted appearance.

Acanthocereus tetragonus is also commonly called the "Organ Pipe Cactus" due to the resemblance of its stems to organ pipes, though this form is more irregular and twisted.

This cactus is perfect for creating a statement piece in a succulent garden or as a standalone specimen.

Its ability to grow tall and spread out makes it a great indoor or outdoor plant, depending on the climate.