Scientific: Aloe ferox
Common: Cape aloe, bitter aloe, tap aloe, áloe del cabo
Family: Asphodelaceae (formerly Xanthorrhoeaceae)
Origin: South Africa (Eastern Cape, Free State, KwaZulu-Natal), and extending inland as far as Lesotho. Aloe is a diverse genus that contains about 500 species found in South Africa from the western Cape and great Karoo into the Orange Free State.
Pronounciation: AL-o FER-ox
Hardiness zones
Sunset 12 and 13 with protection, 16-24
USDA 9-11
Landscape Use: Cape aloe is a great accent plant for xeric gardens, container plant.
Form & Character: Upright, stiff, somewhat uncontrolled, striking, tree like with age.
Growth Habit: Evergreen, succulent, herbaceous perennial that is arborescent in habit producing stems that arch to 10-feet tall, although usually far smaller in Phoenix due to the extreme summer heat.
Foliage/texture: Glaucous-green succulent leaves having a range of short, stout spines (yellow to reddish brown), mostly on the leaf margins. Leaves taper to a blunt tip and are sometimes up to 3-feet long. Old, dried leaves are persistent on the stem and form a dense rattling brown skirt. Cape aloe is strongly coarse textured.
Flowers & fruits: The inflorescence is a candelabra of tubular yellow-orange to red flowers on stalks standing 2 to 4 feet above the leaves. Individual flowers are about 1-inch long, tubular, and are densely packed in thick brushlike clusters on the stalks. Fruit are a multiocarpulate capsule, generally unattractive.
Seasonal color: Brilliantly-colored, spectacular winter flowers.
Temperature: Cape aloe is intolerant of winter freezing temperatures and summer temperatures above 115oF.
Light: As with most Aloe species in central Arizona deserts, light shade or protection from western afternoon sun is best.
Soil: Tolerant, but well drained is best.
Watering: Infrequent irrigations during the summer.
Pruning: None except removal of dead flower stalks.
Propagation: Seed and stem cuttings, occassionally division of basal clumps.
Disease and pests: None
Additional comments: Cape aloe flowers attract hummingbirds when in bloom. Cape aloe is similar in appearance and landscape use to Aloe marlothii. Neither of these to majestic aloes are commonly seen in Phoenix landscapes because of their difficulty in tolerating the exterme summer heat.
Taxonomic tidbit: The species name ferox means "fierce" or "war-like" describing the spiny leaves.
Biomedical factoids: The published medicinal uses of cape aloe are many. The commercial products derived from cultivated cape aloe leaf extracts are similar to those from Aloe vera. Cape aloe extract is renowned for treatment for constipation (an effective laxative) and arthritis. Anyone out there want some exotic Aloe ferox juice?
