|Aloe subsp. var.||Aloe|
The genus is native to Africa, and is common in South Africa's Cape Province, the mountains of tropical Africa, and neighbouring areas such as Madagascar, the Arabian peninsula, and the islands off Africa.
Most Aloe species have a rosette of large, thick, fleshy leaves. The leaves are often lance-shaped with a sharp apex and a spiny margin. Aloe flowers are tubular, frequently yellow, pink or red and are borne on densely clustered, simple or branched leafless stems.
Many species of Aloe appear to be stemless, with the rosette growing directly at ground level; other varieties may have a branched or unbranched stem from which the fleshy leaves spring. They vary in colour from grey to bright-green and are sometimes striped or mottled. Some Aloes native to South Africa are arborescent. 
|Standard Cyclopedia of Horticulture|
Aloe (Arabic name). Liliaceae, tribe Aloineae. Acaulescent or variously caulescent perennial succulents.
Leaves often large, usually crowded in rosettes or along end of st.: fls. red or yellow, often paler-striped, straight, tubular (Fig. 169), with short straight limb, equaled or surpassed by the stamens.—Afr., especially in the Cape region, 1 species about the Medit. and extensively naturalized in all warmer parts of the world, and 1 in China. Plants of the coolhouse, best planted out in a well-drained place in summer, when they flower prettily.
The generic or scientific name Aloe is a Latinized form of an Arabic name. As an English word it is pronounced in two syllables, thus Al-oe. Popularly this word is loosely used, the common American aloe being Agave americana, the commonest "century plant." The "bitter aloes" of commerce is a resinous juice much used as a laxative. The best quality is called "Socotrine or Zanzibar aloes," a product of A. Perryi, which was known by the Greeks of the fourth century B.C. to come from the island of Socotra. The "Barbadoes aloes" is the product of planted in the West Indies. Genera allied to Aloe are Apicra, Gasteria, Haworthia, Pachidendron, and Phylloma. The group is difficult for the botanist, there being few authentic specimens in the herbaria, because of the large size of the plants, the infrequent flowering, and the difficulty of suitably drying them. Monograph by Alwin Berger in Das Pflanzenreich, 1908, hft.33.
Propagation is by seed, which usually is not true to name, and by suckers or cuttings well dried-off. Branching for this purpose may be induced by searing the crown of old plants. Hybrids between the different species and with related genera are easily secured and interesting.
Aloes are much cultivated as decorative plants, being amongst the most popular of desert and succulent plants for their stiff, harsh and rugged habit. Fig. 170. They are often grouped about large public buildings, where they emphasize certain architectural features. Large collections are to be seen only in botanic gardens and in the collections of a few fanciers. The largest dealer has nearly one hundred kinds, but grows only five or six kinds in quantity.
Old plants of Aloe will keep healthy for several years in the same pots without a renewal of soil, and flower freely at the same time. The soil most suited to their needs is sandy loam three parts, lime rubble and broken brick one part, with a little decayed manure to strengthen the mixture. Very firm potting is necessary. Drainage is a more important item than soil, and must be perfectly arranged to enable the surplus water to run freely from the soil. Broken bricks are preferable to pieces of pots, large pieces for the bottom of the pot or tub, and smaller pieces above, till the last layer is quite fine. Some of the species need freer rooting conditions than others. A. ciliaris will grow from 5 to 7 feet in a season. A. abyssinica is of robust growth, and differs from most others in the color of the flowers, which are pure yellow, the others being mostly orange and orange-scarlet. A.plicatilis makes an ornamental tub plant when 4 or 5 feet high. Except during the period in which the species are in active growth, they need very little water, the principal idea being to keep the soil sweet and porous even when in growth. At all times the air of the house should be as dry as possible, full sunshine not hurting them. Propagation is by seeds, suckers and cuttings. The arborescent kinds should be rooted after they have completed growth. Dust over the cut part of the cutting with powdered charcoal and dry in sunshine before putting it in to root. Insert singly in as small pots as they will go into, and plunge in a sand-bed. Very little moisture is necessary while rooting.
Pests and diseases
There are around 400 species in the genus Aloe. For a full list, see List of species of genus Aloe. Species include:
- Aloe vera - used in healthcare & health products
- Aloe arborescens - used in healthcare
- Aloe aristata - Torch Plant, Lace Aloe
- Aloe dichotoma - quiver tree or kokerboom
- Aloe nyeriensis
- Aloe variegata - Partridge-breasted Aloe, Tiger Aloe
- Aloe barbadensis - Barbados Aloe, Common Aloe, Yellow Aloe, Medicinal Aloe. This is an older name for Aloe vera.
- Aloe wildii
The APG II system (2003) placed the genus in the family Asphodelaceae. In the past it has also been assigned to families Aloaceae and Liliaceae or lilly family. Members of the closely allied genera Gasteria, Haworthia and Kniphofia, which have a similar mode of growth, are also popularly known as aloes. Note that the plant sometimes called American aloe (Agave americana) belongs to Agavaceae, a different family.
|Standard Cyclopedia of Horticulture|
-A. Cameronii. Hemal. Fls. almost cinnabar-red, passing into yellow toward the top. E. Trop. Air. —A. Campylosiphon, A. Berger. Pale yellow us. E. Trop. Afr. —A. Chabaudii, Schoenl. Allied to A. stricta. Lvs. bordered with small prickles; outer segms. of fls. pale brick-red with whitish wings at apex. Trop. Afr. —A. decora, Schoenl. A dwarf species having red fls. tipped with green. S. Afr. —A. Lastii. Baker. Fls. pale yellow, greenish at top. Zanzibar.—A. laxiflóra, Hort. Very lax arrangement of fls. which are orange-red in lower part and yellow at apex. Cape Colony. —A. Marlothii, A. Berger. Extremely spiny lvs. and nearly horizontally spreading fl.-spikes. British Bechuanaland. —A. Orpenae, Schoenl. Lvs. lined with white spots and markings on both surfaces: fls. red, tipped with white. S. Afr. —A. pallidiflora, A. Berger. A stemless plant: lvs. armed on margins with sharp spines: fls. pale flesh-color. 3. Afr. —A. pendent. A shrubby species: fls. drooping, dull yellowish red. S. Arabia. —A. rubrolutea, Schini. Unbranched st. 8 ft. high or more: lvs. armed or margins with brown deltoid and somewhat hooked spines: fls. bright red. Trop. S. W. Afr.
- Standard Cyclopedia of Horticulture, by L. H. Bailey, MacMillan Co., 1963