Aloes are a group of succulent plants that are becoming more and more popular for landscaping purposes. They are native to the Old World: the African mainland; the Arabian Peninsula; and the islands of Socotra, Madagascar, and Comoro. These plants are diverse both in form and color and can be arborescent, stemless, clumping or solitary. Aloes range in height from 6 inches to 60 feet. The leaves can be spotted, striped, gray, bright green or even red. Flowers range from red to orange, pink, yellow, green, white and even bicolored. These plants bloom yearly in winter months when not much else is blooming. Everyone is familiar with Aloe vera and its medicinal qualities, however, it is just one of about 450 species of aloe. Not all aloes are medicinal – some are actually poisonous. Never put just any aloe juice on your skin – they are not all the same! Aloes are best grown outdoors in filtered light or on a bright patio. Only the smaller species should be kept in a container. The larger varieties can start out containerized but will rapidly outgrow their pots and should be moved to the landscape, depending on the species, where they enjoy free root run. SOIL: Aloes need a well-drained soil and do best with a mixture of 4 parts organic-based cactus mix, 2 parts pumice and 1 part grit (e.g. #12 silica sand). Be sure any container used has a drainage hole.
WATER: Aloes need supplemental water to thrive. Most species should be watered once a week during the summer and then less for lower temperatures during spring and fall. In the winter, depending on cold and humidity, container plants should be watered about once a month.
LIGHT: Aloes need bright light, although most will not tolerate full sun. A 50% shade factor is ideal for most species. It is a fallacy that aloes tolerate deep shade – they will, in fact, grow out of proportion in this situation.
FERTILIZATION: Aloes can be fertilized with a low nitrogen water-soluble fertilizer at low strength each watering or at full strength once a month spring through fall.
PROPAGATION: Aloes can be propagated as cuttings from offshoots or from seed. The clumping species can be pulled apart and the pieces rooted in pumice. Solitary species can only be started from seed. Clumping varieties that have grown too large for the container can be unpotted and separated.
TRANSPLANTING/REPOTTING: Aloes can be planted in the ground, if the species is appropriate, at almost any time of the year, although spring through fall is best. Roots should be gently loosened, especially if the plant is pot-bound, and the plant placed in the hole and back-filled. An amendment is not necessary. The technique is the same if repotting to a larger container. However, if a different soil mix is used, all of the old soil should be gently removed first, with care being taken not to damage the succulent roots. In both cases, plants should be planted dry and should not be watered in for at least one week.
PESTS AND DISEASES: Aloes have few diseases and pests outside of a greenhouse situation. A problem becoming increasingly common is aloe mite damage. Although the mite is not visible, the damage manifests itself as a cancerous growth on the leaves and inflorescences. It causes distortion of the leaves and flowers and, at its worst, looks like the leaf has exploded from the inside out. If extensive, destroy the entire plant. A systemic pesticide can be applied according to label instructions. Another common problem on some species is crown rot, which can occur during the humid monsoon period of July and August. If the rot has traveled completely down the main stem, it is probably too late. Otherwise, apply a systemic fungicide suitable for wet rot. It is also possible to cut out the rot if you are careful not to destroy the growing point. Apply fungicide and let dry.