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Cape Aloe
Aloe ferox · Asphodelaceae (formerly Liliaceae/Aloeaceae)
Also called: Bitter Aloe, Red Aloe, Tap Aloe, Cape Aloe
Cape Aloe (Aloe ferox) is a low-water accent well suited to Tucson and the low desert. It thrives in full sun, with a slow to moderate growth rate.
Cape Aloe at a glance
- Water use
- Low (established)
- Sun
- Full sun; tolerates reflected heat better than Aloe vera, though light afternoon shade reduces leaf scorch in peak summer.
- Mature size
- 6-10 ft H x 3-4 ft W (single-stemmed tree aloe); flower stalk adds 2-4 ft above the rosette
- Growth rate
- Slow to moderate
- Bloom
- Bright orange-red to scarlet (occasionally orange or yellow forms), Winter to early spring (roughly December-March), in showy candelabra of erect racemes — a major cool-season nectar source
- Cold hardiness
- Hardy to about 25°F, briefly into the low 20s; USDA zones 9-11. One of the more cold-tolerant large aloes, but can show frost damage in hard Tucson freezes.
- Soil
- Fast-draining gritty, sandy, or rocky soil. Needs excellent drainage; intolerant of standing water and heavy clay.
- Native range
- Native to South Africa (Western and Eastern Cape, Lesotho). Not native to the Sonoran Desert.
- Best used as
- Accent/specimen focal point, Dramatic winter color, Succulent and cactus gardens, Large containers (young plants), Pollinator/hummingbird gardens, Architectural silhouette plantings
- Wildlife
- Outstanding winter nectar source — flowers heavily visited by hummingbirds, orioles, bees, and other pollinators when little else blooms. Deer-resistant.
- Toxicity
- The bitter yellow leaf latex (source of commercial 'bitter aloes'/aloin, a laxative) is toxic and irritating if ingested. Considered toxic to pets; the spiny leaf margins can also cause injury.
How to grow Cape Aloe in Tucson & the low desert
Watering
Very drought tolerant once established. Water deeply every 2-3 weeks in summer and little in winter. Established specimens survive on minimal supplemental water in Tucson.
Fertilizer & nutrients
Little to none. An optional light spring feeding with a balanced or low-nitrogen fertilizer supports bloom and growth but is not required in desert soils.
Pruning & care
Leave dried leaves as a natural skirt on the trunk, or carefully remove them for a clean stem. Cut spent flower stalks after bloom. No shaping needed — it forms a single dramatic rosette atop a trunk.
Notes
A large, robust single-stemmed 'tree' aloe with broad blue-green to reddish leaves armed with reddish-brown marginal and surface spines. The showy candelabra of red-orange winter flowers makes it one of the best cold-season accents for the low desert. More cold- and sun-hardy than Aloe vera, making it well suited to Tucson as a bold specimen.
Sources: Arizona-Sonora Desert Museum; University of Arizona Cooperative Extension; AMWUA / low-desert succulent references; Tohono Chul / Tucson Botanical Gardens