Aloe Plant Information and Variety Selection

The Aloe genus is diverse and belongs to the family Asphodelaceae, with over 500 known plant species of diverse sizes, shapes, and functionalities. Native to Africa and parts of the Arabian Peninsula, these perennial succulents thrive in hot, arid environments, and they are widely distributed globally due to their adaptability and medicinal properties. One of the most well-known and commercially significant varieties is Aloe vera (Aloe barbadensis Mill.), which has been used for centuries for its healing, cosmetic, and dietary benefits. Other varieties also hold significant medicinal and ornamental value but remain underutilized in the global market.

Botanical Characteristics

The leaves of Aloe plants are notable for their fleshy texture and serrated edges, often reaching lengths of 30 to 60 cm or 11 to 23 inches (depending on the species). Each leaf consists of three distinct layers: an inner gel layer rich in water and nutrients, a middle layer of latex that contains bitter compounds, and an outer rind that provides protection and structural support. The inner gel, which comprises about 99% water, contains vital substances such as glucomannans, amino acids, lipids, sterols, and vitamins. This composition contributes to the renowned medicinal properties of certain Aloe species.

The flowers of Aloe are tubular and can range in color from yellow to vibrant red. They typically appear in spikes, attracting pollinators such as sunbirds. The flowering process in Aloe is interesting; while individual plants possess both male and female reproductive organs, successful fertilization requires cross-pollination between different plants.

Importance of Aloe Plants

Aloe species have been revered since ancient times for their wide-ranging medicinal properties. Aloe vera, often referred to as the "miracle plant," is known for its soothing, moisturizing, and healing properties. It has applications in treating skin conditions, aiding digestion, and promoting overall health. Despite Aloe vera's fame, other species, such as Aloe arborescens and Aloe ferox, also offer commercial potential. For example, Aloe arborescens was used to treat radiation burns after the Hiroshima bombing and is currently under commercial development for its gel products in Japan and Italy.

Aloe Varieties and Their Uses

Various species of aloe offer unique benefits beyond the well-known Aloe vera. Some species have medicinal properties, while others serve decorative and environmental functions.

Aloe-Barbadensis

***Aloe barbadensis (*Aloe Vera**)

This is the most commercially important and most cultivated variety, known for its wide use in skincare, pharmaceuticals, and dietary supplements. It contains a vitamin-rich gel, amino acids, and other nutrients. This species is an evergreen perennial native to the Arabian Peninsula. The plant can grow up to 24-39 inches (60-100 cm) tall and features thick, fleshy leaves with serrated margins.

Aloe arborescens

Known as “Candelabra Aloe,” this variety can grow up to 10 ft (3 m) tall. Its cylindrical flowers and vigorous growth make it a popular ornamental plant. Aloe arborescens aids wound healing and boosts the immune system. This variety is a promising candidate for gel production, similar to Aloe vera.

Aloe-Ferox

Aloe ferox

Commonly called "Red Aloe" or "Cape Aloe," this variety is native to South Africa. It can reach up to 10 ft (3 m) in height and has red flowers. Its leaves contain a natural laxative, and its seed oil is used in skincare products. Its high content of linoleic and oleic acids makes it valuable in the cosmetic industry. It is also an alternative source for natural laxatives.

Aloe striata

Often referred to as "Coral Aloe," it thrives in hot, arid climates. Its smooth leaves with pink-tinted spikes make it a popular choice for ornamental use. Aloe striata has been studied for its potential benefits to human digestion. It thrives in hot, dry conditions, making it an excellent choice for indoor spaces.

Aloe aristata

Also known as "Lace Aloe," this variety is cherished for its unique white spots and serrated leaves. It is a hardy garden plant, ideal for warmer climates, and attracts bees and other pollinators.

Aloe marlothii

Also known as "Mountain Aloe" or "Flat-Flowered Aloe," it is a large, single-stemmed plant that can grow up to 20 ft (or 6 m) tall. This species has a robust head of stiff, grey-green leaves that can reach lengths up to 5 ft (1.5 m). The inflorescence is distinctively horizontal, featuring a much-branched panicle with flowers that vary in color from yellow to bright red. This adaptation helps it thrive in rocky, open areas across Southern Africa, including regions from Johannesburg to Zimbabwe and Malawi. It is distinguished for its ornamental uses.

Aloe Chinensis

This variety is popular among gardeners because of its ornamental beauty and does not require a lot of care.

Aloe humilis

Also referred to as “spider aloe”, this variety is native to South Africa's Cape Province. It features a short stem and small spines, typically forming dense clusters. Its gel has been noted for its soothing properties on sunburn.

Aloe barberae (Aloidendron barberae)

Commonly known as the "Tree Aloe," this species is native to subtropical coastal forests in South Africa and Mozambique. It is Africa's largest aloe-like plant, capable of reaching heights up to 60 ft (18 m) with a stem diameter of 36 inches (91 cm). The Tree Aloe features rose-pink tubular flowers that bloom in winter, typically pollinated by sunbirds. This slow-growing tree is prized for its ornamental and for its medicinal properties, particularly its soothing qualities.

Aloe polyphylla

Often referred to as "Spiral Aloe," this highly sought-after ornamental variety is known for its striking spiral leaf arrangement and vibrant flowers. It grows on high, mountainous grassy slopes at altitudes between 6.5 and 8.5 ft (2 and 2.6 m). It thrives in rocky crevices and well-drained scree slopes in regions with cool summers and heavy snowfall in winter. Its beauty has led to overharvesting, making it a rare find.

Kumara plicatilis:

Formerly known as Aloe plicatilis, this species, commonly called "Fan Aloe," is endemic to the Fynbos ecoregion in the Western Cape of South Africa. It has a unique fan-like arrangement of leaves and can grow as a large, multi-stemmed shrub or a small tree. Aloe plicatilis is typically found on steep, rocky south-facing slopes in sandy, slightly acidic soil. While not endangered, it faces threats from illegal collection for the horticultural trade.

Aloe Dicotoma (Aloidendron dichotomum)

Known as the "Quiver Tree" or "Kokerboom," this tall, branching succulent is indigenous to Southern Africa, particularly in the Northern Cape province of South Africa and parts of Southern Namibia. The Quiver Tree Forest, located near Keetmanshoop in Namibia, showcases this unique species. Unfortunately, Aloe dichotoma is experiencing population declines due to climate change, which threatens its natural habitats. It is currently classified as critically endangered.

Selection Criteria of Aloe Variety for Cultivation

When selecting an aloe variety for cultivation, you must consider factors such as climatic adaptability, medicinal value, and market demand.

Climatic Requirements: Aloe plants generally thrive in hot, arid environments and require full sun exposure. Most species do not tolerate cold temperatures, making it essential to grow them in regions with mild winters or provide protection from temperatures below 41°F or 5°C. Aloe vera, for example, grows best in sandy, well-drained soils and is tolerant of poor soil conditions.
Soil and Watering: Aloe species prefer sandy or slightly alkaline soils (ideal pH 7-8.5) with excellent drainage. During hot months, the plants should be watered abundantly, but only when the soil is completely dry. Overwatering, especially during winter, can harm the plant’s health. Therefore, soil moisture should be closely monitored.
Fertilization and Maintenance: Aloe plants should be fertilized sparingly, typically once a month during the growing season (from May to October in the north hemisphere). Pruning is generally not necessary unless damaged leaves are present, which can carry pests and diseases.
Propagation: Aloe plants can be propagated through division, suckers, or rhizome cuttings. While Aloe vera takes 1-2 years to mature, the plant can live and reproduce for up to 15-25 years, making it an excellent long-term investment for commercial cultivation.