Acanthocereus tetragonus (L.) Hummelinck
Barbed Wire Cactus, Dildo Cactus, Night-blooming Cereus, Triangle Cactus, Sword Pear
Acanthocereus colombianus, Acanthocereus floridanus, Acanthocereus pentagonus, Acanthocereus pitajaya, Acanthocereus princeps, Cactus pentagonus, Cactus pitajaya, Cactus prismaticus, Cactus reptans, Cactus tetragonus, Cereus dussii, Cereus nitidus, Cereus pentagonus, Cereus pitajaya, Cereus princeps, Cereus prismaticus, Cereus reptans, Cereus tetragonus, Cereus undulatus, Cereus variabilis, Cereus vasmerii
Acanthocereus tetragonus is a columnar cactus with dark green stems with usually 3 to 5 ribs and clusters of spines along the outer edge of the ribs. It grows up to 23 feet (7 m) tall, branched near the base, sometimes with well-developed trunks. Stems are up to 3 inches (8 cm) in diameter. Areoles are grey and up to 1.2 inches (3 cm) apart. Each areole bears 1 to 2 central and 6 to 8 radial spines. The spines are up to 1 inch (2.5 cm) long. Flowers are up to 8 inches (20 cm) in diameter and 6 inches (15 cm) long. Outer tepals are greenish-white, inner tepals are pure white, and pistils are creamy white. The bright red fruits are ovoid to oblong and up to 3.2 inches (8 cm) long.
USDA hardiness zones 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. Ensure they receive enough water without becoming waterlogged, especially during the summer, and fertilize them for the 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. Most gardeners interested in cacti should be able to cultivate these without much problem.
It may become necessary to repot your Cereus if it outgrows its container. If so, ensure the soil is dry and remove the pot. Knock away old soil, prune away any rotted or dead roots, then replace it in a new pot and backfill with fresh soil. Ensure 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.
These cacti propagate quite easily from cuttings. Simply sever a branch and replant in moist, well-drained soil.
Learn more at How to Grow and Care for Cereus.
Forms and Cultivars
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