Acanthocereus tetragonus (Triangle Cactus)

Scientific Name

Acanthocereus tetragonus (L.) Hummelinck

Common Names

Triangle Cactus, Barbed Wire Cactus, Sword Pear, Dildo Cactus, Night-Blooming Cereus

Synonyms

Cactus tetragonus (basionym), Cereus tetragonus, Acanthocereus pentagonus, Acanthocereus pitajaya, Cactus pitajaya, Cereus pitajaya, Cactus pentagonus, Cereus pentagonus, Cereus pentagonus, Cactus pentagonus, Cereus acutangulus, Acanthocereus acutangulus, Cereus princeps, Acanthocereus princeps, Cereus princeps, Cereus variabilis, Acanthocereus floridanus, Acanthocereus colombianus, Cactus prismaticus, Cereus prismaticus, Cactus reptans, Cereus reptans

Scientific Classification

Family: Cactaceae
Subfamily: Cactoideae
Tribe: Echinocereeae
Genus: Acanthocereus

Description

Acanthocereus tetragonus is a tall, columnar cactus up to 23 feet (7 m) tall. The stems are dark green with usually 3 to 4 angles and up to 3 inches (8 cm) in diameter. Areoles are grey, up to 1.2 inches (3 cm) from each other. Central areoles have 1 to 2 (sometimes 3) spines up to 1.6 inches (4 cm) long. Radial areoles have 6 to 8 (sometimes up to 10) spines up to 1 inch (2.5 cm) long. The flowers are up to 8 inches (20 cm) in diameter with a tube up to 6 inches (15 cm) in length. Outer tepals are greenish-white, inner tepals are pure white, and pistils are creamy white. The shiny, red fruits are up to 2 inches (5 cm) long.

Photo via karenmelody.com

Hardiness

USDA hardiness zone 9a to 11b: from 20 °F (−6.7 °C) to 50 °F (+10 °C).

How to Grow and Care

Like most cacti, Cereus are fairly low-maintenance and hardy. Make sure they receive enough water without becoming waterlogged, especially during the summer, and fertilize them for best results. If the roots have become black or overly soft, the cactus could be experiencing root rot – cut away the affected parts and replant.

It may become necessary to repot your Cereus if it outgrows its container. If so, make sure the soil is dry and then remove the pot. Knock away old soil and prune away any rotted or dead roots, then replace it in a new pot and backfill with new soil. Make sure not to overwater cacti planted in new pots, as this can lead to root rot – it should be left dry for about a week and then watered lightly… – See more at: How to Grow and Care for Cereus

Origin

Native to Southern Florida and the Lower Rio Grande Valley of Texas in the United States, Mexico, Central America, Caribbean, and northern South America.