The krantz aloe is a valuable garden asset, it has large beautiful
flowers, attractive foliage, decorative form, and it is easy to
grow. It is also a 'must-have' for anyone wanting to stock their
herb gardens with indigenous healing plants.
krantz aloe develops into a multiheaded shrub 2 -3m high with striking
grey green leaves arranged in attractive rosettes. The leaf margins
are armed with conspicuous pale teeth.
large colourful flower spikes are borne in profusion during the
cold winter months (May-July), brightening up a drab winter garden.
Deep orange is the most common colour, but there are also pure yellow
forms, and an unusual bi-coloured form of deep orange (almost red)
and yellow. The inflorescence is usually unbranched, with two to
several arising from a single rosette. As with all the aloes, the
flowers produce nectar and are attractive to many kinds of birds,
in particular the small and colourful sunbirds, which flit from
flower to flower in search of nectar. The flowers also attract bees.
The species formerly known as Aloe mutabilis
is now regarded as a synonym of Aloe arborescens. It is a
cliff dwelling form with smaller, less branched rosettes and red
& yellow bi-coloured flower spikes and is more evident on the
high inland plateau of the northern provinces of South Africa. This
cliff dwelling form of Aloe arborescens can be seen hanging
from the cliffs alongside the waterfall at the Witwatersrand National
Although it is in fact a large much-branched shrub, Aloe arborescens
has been allocated a national tree number (28.1).
This species is distributed mainly over the eastern, summer rainfall
areas of the country. It has the third widest distribution of any
aloe, occurring from the Cape Peninsula along the eastern coast,
through KwaZulu-Natal, Mpumalanga and Limpopo province and further
north into Mozambique, Zimbabwe and Malawi. It is one of the few
aloes that can be found growing at sea level right up to the tops
of mountains. The krantz aloe is adapted to many habitats, but is
usually found in mountainous areas where it favours exposed ridges
and rocky outcrops. It is also found in dense bush.
Derivation of the name & historical aspects
The name aloe is from the Greek alsos and refers to the bitter
juice from the leaves of these plants. It is probably derived from
the earlier Arabic word alloeh or the Hebrew word allal,
both meaning bitter. The Latin word arborescens means tree-forming
or tree-like, and is a bit misleading in that this aloe is not really
tree-like, but the name was originally applied to this species in
reference to the stem-forming habit. The common name krantz aloe
refers to its habitat, a krantz being a rocky ridge or cliff.
Aloe arborescens is one of approximately 130 Aloe
species native to southern Africa. It is possibly the most widely
cultivated aloe in the world and can be seen grown in gardens in
many cities around the world. It was one of the first South African
aloes collected and planted in the Company's Garden in Cape Town.
It was grown in Amsterdam by Professor Commelin in 1674, and featured
in Hort. Amst. 2 in 1701.
Uses and cultural aspects
In many parts of South Africa Aloe arborescens is planted
around kraals (domestic stock enclosures) as a living fence. It
often happens that the position of old kraals can still be seen
many years after they have been abandoned because the aloes persist.
Cuttings intended for use as barrier plants are sold in muthi shops.
The Zulu people use the leaves of this plant, dried and pounded
into a powder, as a protection against storms. Decoctions of the
leaves are also used in childbirth and in treating sick calves.
In the Transkei it is used for stomach ache and given to chickens
to prevent them from getting sick. In the Orient, this aloe is grown
in domestic gardens as a convenient first-aid treatment for burn
wounds and abrasions. In fact it was only after it was used to treat
irradiation burn victims of Hiroshima that its healing properties
received attention from the West. Extracts from the leaves have
been widely investigated since then and shown significant wound
healing, anti-bacterial, anti-ulcer, anti-inflammatory, anti-carcinogenic,
hypoglycaemic and also alopoeic activity. The leaves have also been
found to have purgative properties and the leaf sap is reported
to relieve x-ray burns.
Growing Aloe arborescens
The krantz aloe is an easy and rewarding plant to grow, and is
a popular garden plant in many countries. It enjoys full sun, well-drained,
compost-enriched soil and can tolerate moderate frost but is sensitive
to severe frost. It is fast-growing, and it will tolerate drought
and neglect once established. It is grown mainly as an ornamental
or as an accent plant, but is also an excellent and impenetrable
The krantz aloe is easily propagated from a branch or stem cut
off, allowed to dry for a day or so until the wound has sealed,
and then planted in well-drained soil or sand. They need not be
rooted in any particular place and then transplanted, but can be
placed directly into their permanent place in the garden. It is
important to remember not to water the cuttings too heavily; overwatering
may cause them to rot. This aloe can also be grown from seed, sown
in spring. Seed should take three to four weeks to germinate, and
the seedlings must be protected from frost.
Aloe arborescens hybridises readily with other aloes.
- Van Wyk, B.E. & Smith, G. 1996. Guide to the Aloes of
South Africa. Briza Publications, Pretoria.
- Jackson, W.P.U. 1990. Origins and Meanings of Names of South
African Plant Genera. U.C.T. Printing Dept., Cape Town.
- Hutchings, Anne. 1996. Zulu Medicinal Plants, an inventory.
University of Natal Press, Pietermaritzburg
- Palmer, E. and Pitman, N. 1972. Trees of Southern Africa.
A.A. Balkema, Cape Town.
- van Wyk, B.E., Gericke, N. 2000. People's Plants. Briza
- Leistner, O.A. (ed.). 2000 Seed plants of southern Africa: families
and genera, Strelitzia 10. National Botanical Institute,
Andrew Hankey (2001) & Alice Notten (2004)
Witwatersrand NBG & Kirstenbosch NBG
May 2001 updated