This form of Aloe arborescens used to be known by the species name "mutabilis" which means changeable or mutable. This epiphet probably refers to the flowers which change colour as they open and to the variability of the species. Fairly recently it has been formally combined under Aloe arborescens to which it has affinities.

Aloe mutabilis grows naturally on vertical rock faces of Witwatersrand National Botanical Garden at the Witpoortjie waterfall, which is the type locality. It occurs also at Chuniespoort near Pietersburg and westwards along the Magaliesburg to Rustenburg. This form of Aloe arborescens is less widely distributed than the more commonly known Aloe arborescens, but it can be found in the hilly and mountainous area of the former southern and central Transvaal. It is not a threatened species.

Aloe mutabilis is a beautiful aloe with a trailing stem up to 1 metre long with offshoots. Its stem hangs downward with the rosettes of leaves turned up at an angle. This aloe has many leaves, 60-70cm long. The upper surfaces are glaucous green to dull green with brownish to yellow margins. The leaf margins are armed with harmless, yellowish orange teeth. The shape of the spaces between the teeth is straight, not rounded as with the commonly known Aloe arborescens.

The inflorescence of this aloe is simple, up to 90cm high, but sometimes with 1 to 2 branches. It has a bicoloured raceme. Individual flower buds are red buds and then on opening the flowers turn yellow or greenish yellow. The flowers of some forms are uniformly red. Flowering time is winter, from May to July, depending on the regional climate. Aloes in the Northern Province may flower at a different time to those at Witpoortjie waterfall.

The commonly known pollinating agents are nectar feeding birds, bees and wind.

Growing Aloe mutabilis

Aloe mutabilis is easily cultivated from seeds and offshoots. The offshoots can be planted straight into river sand. Its bicoloured racemes make it a popular garden plant in highveld gardens. Aloe mutabilis grows fairly fast and it can withstand fairly severe frost. It makes a magnificent rockery specimen when grown at the highest point of the rockery with the rosette hanging downward.

Thompson T. Mutshinyalo
Walter Sisulu National Botanical Garden
June 2001