Acanthocereus tetragonus, commonly known as the Fairy Castle Cactus or Triangle Cactus, is a succulent plant that is native to a variety of habitats including coastal hammocks, rocky outcrops, and arid scrublands in Florida, Texas, Mexico, Central America, and the Caribbean. It is a slow-growing cactus that can reach heights of 7-23 feet with distinctive dark green, three- to six-angled stems that give it a sculptural appearance. The plant is notable for its large, showy white flowers that bloom at night, typically during the summer months, and are pollinated by nocturnal creatures such as bats and moths. Following flowering, it produces edible red fruits that are attractive to wildlife.

The Fairy Castle Cactus is valued for its unique architectural form and is often used in xeriscaping, rock gardens, and as a striking container plant. It requires minimal maintenance, making it suitable for gardeners seeking drought-tolerant options. In cultivation, it prefers full sun to partial shade, well-draining soil, and infrequent watering to mimic its natural dry habitat. While it is used as a living fence in some regions, care should be taken as its spines can be sharp. It is also important to note that while the plant is generally disease-resistant, it can be susceptible to root rot if overwatered.CC BY-SA 4.0