Cactus
Argentine Giant
Echinopsis candicans · Cactaceae
Also called: Soehrensia candicans (currently accepted under POWO), Trichocereus candicans (synonym), Cereus candicans (synonym), White Torch Cactus
Argentine Giant (Echinopsis candicans) is a low-water cactus well suited to Tucson and the low desert. It thrives in full sun in the low desert.
Argentine Giant at a glance
- Water use
- Low (established)
- Sun
- Full sun in the low desert; tolerates reflected heat. Light afternoon shade reduces summer scald on young plants.
- Mature size
- 12-24 in H x 3-5+ ft W (low, sprawling clusters of many stout columnar stems forming a broad clump)
- Growth rate
- Moderate (vigorous and clump-forming compared with most hedgehogs)
- Bloom
- Large, fragrant, white flowers (8-10+ in long), opening at night and lasting into the following morning, Late spring to early summer (April-June), often in a spectacular single-night mass display.
- Cold hardiness
- Hardy to about 10-15 F (USDA zones 8b-11); may show tip damage in hard low-desert freezes but recovers.
- Soil
- Well-drained sandy, gravelly, or loamy soils; tolerant of a range of garden soils as long as drainage is good. Avoid soggy ground.
- Native range
- Native to the Andean foothills and dry scrub of western Argentina (Mendoza, San Luis, Córdoba region); not native to North America. Widely grown as a landscape ornamental in Tucson.
- Best used as
- Bold flowering accent / specimen, Mass and clumping cactus plantings, Low borders and median/parking-strip plantings, Container culture, Night-garden and fragrance plantings
- Wildlife
- Big, fragrant nocturnal flowers attract night-flying pollinators such as hawkmoths; daytime visitors include bees. Not a native habitat plant.
- Toxicity
- Non-toxic. The stout, sharp spines are the main hazard.
How to grow Argentine Giant in Tucson & the low desert
Watering
More forgiving of water than native hedgehogs: deep watering every 2-3 weeks in the hottest summer months promotes growth and bloom, tapering to little or none in winter. Still requires good drainage to avoid rot.
Fertilizer & nutrients
Benefits from a light spring feeding with a balanced or low-nitrogen cactus fertilizer to support its vigorous growth and large blooms; avoid heavy nitrogen.
Pruning & care
No formal pruning. Remove damaged stems and let cuts callus; offsets/stems can be removed to control spread or for propagation.
Notes
Popular, tough Tucson ornamental valued for its huge, fragrant white night-blooming flowers and easy clumping habit. Taxonomy is unsettled: Plants of the World Online now places it in Soehrensia candicans, while Echinopsis candicans and Trichocereus candicans remain in common horticultural use. Non-native (Argentina) but well adapted to the low desert.
Sources: AMWUA / ASU Plant Database (C. Martin); Plants of the World Online (Kew); Arizona-Sonora Desert Museum; University of Arizona Cooperative Extension