Acanthocereus tetragonus (Fairy Castle Cactus)

Acanthocereus spp.

barbed-wire cactus

Cactaceae Tropical and subtropical Americas

Attracts Pollinators Deer Resistant Drought Tolerant Fragrant (moderate)Container Friendly

Native to North America

SunFull Sun – Part Shade

WaterLow · drought-tolerant

HardinessZones 10–12

Overview

Acanthocereus spp. is a genus of sprawling, clambering cacti in the family Cactaceae, with about eight species native to the tropical and subtropical Americas. Stems are slender and green, 2–7 cm (0.8–2.8 in) thick, with three to five sharp ribs lined with clusters of stout spines, and they arch, lean, and scramble over other plants to lengths of 2–7 m (6.5–23 ft). New growth is erect before bending and rooting where it touches the ground, forming dense, tangled thickets. Large funnel-shaped flowers 12–25 cm (5–10 in) long open at night, white inside with greenish outer segments, and are pollinated by moths and bats before closing by mid-morning. Red, fleshy, spiny fruits 3–5 cm (1.2–2 in) long follow and are edible. Acanthocereus spp. grows in full sun to light shade on free-draining sandy or rocky soil in frost-free climates, tolerating drought, heat, and salt spray, but it is damaged by frost and rots in wet, poorly drained ground. The spreading, spiny stems form barriers that are hard to remove once established.

Native Range

Acanthocereus spp. is native to the tropical and subtropical Americas, from the southern United States in Florida and Texas through Mexico, Central America, and the Caribbean into northern South America. It grows in coastal scrub, dunes, dry forests, and thickets, mostly at low elevations.

Suggested Uses

Grown as a spiny barrier or screen, in cactus and dry gardens, and trained on walls and fences in frost-free regions. Planted for its night flowers and edible fruit. Suited to hot, dry, low-water sites rather than cool or wet gardens.

How to Identify

Recognised by long, slender, three- to five-angled green stems with sharp spines that lean and scramble rather than stand upright. The large white night-opening flowers and red spiny fruits are characteristic. Where stems touch the soil they root, building tangled, spiny thickets.

Appearance

Size & Dimensions

Height6' - 23'

Width/Spread6' - 15'

Reaches mature size in approximately 4 years

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~8 weeks

Spring Summer

Acanthocereus spp. flowers in the warm, wet season, generally late spring through summer. The large flowers open after dark and close by the next mid-morning, each lasting a single night. Red fleshy fruits ripen several weeks after flowering.

Detailed Descriptions

Flower Description

white with green

Foliage Description

green stems (leafless)

Growing Conditions

Sun Requirements

SunFull Sun SunPartial Shade

Requires 6-12 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range6.0 - 7.5(Neutral)

357912

Soil Types

sand rocky loam

Drainagewell drained

Water & Climate

Water Needs

Low

Frost Tolerance

tender

Time to Maturity

2-4 years to flowering

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Grow Acanthocereus spp. in full sun to light shade on sharp, free-draining sandy or rocky soil. It tolerates drought, heat, poor ground, and coastal salt but needs frost-free conditions and rots in wet, heavy, or shaded sites. A soil pH from about 6.0 to 7.5 suits it. Water occasionally in the growing season and keep it dry in cool weather. The scrambling stems need a support, wall, or open ground to spread across. Established plants need little care beyond containment.

Pruning

Prune Acanthocereus spp. to control its spread and remove stems that have rooted beyond their space. Cut stems back to a joint at any time in warm weather, and let the cut ends callus before they are moved. Thinning the tangle improves air flow and flowering.