The fever tree is an attractive, semi-deciduous to
deciduous tree approximately 15 to 25 meters tall and has an open,
rounded to spreading or flattish crown which is sparsely foliated.
The characteristic, almost luminous, lime green to greenish-yellow
bark is smooth, slightly flaking, and coated in a yellow powdery
substance described by some as sulphurous. If the powdery surface
is rubbed away with the finger it will reveal a green bark beneath.
Young twigs have a red-brown bark which peels off leaving the twigs
sulphur yellow. The long straight white thorns are arranged in pairs
and although they are very significant on young trees they often
become barely noticeable on mature specimens.
Bright yellow, golden, ball-like flowers which are sweetly scented
are borne in clusters on shortened side shoots at the nodes and
towards the ends of branches. Flowering occurs from August or September
to November. Flowers are followed by the production of yellowish-
brown to brown pods which split open to reveal the small hard brown
seeds, which may be harvested from January to April.
The genus name Acacia is derived from the greek word acantha
meaning spine, thorn or prickle and the species name xanthophloea
is derived from the greek words xanthos meaning yellow and
phloios meaning bark.
The fever tree occurs mainly in depressions and shallow pans where
underground water is present or surface water collects after summer
rains. It is also found in low-lying swampy areas, along the margins
of lakes and on river banks. It often forms pure, dense stands of
closed woodland in seasonally flooded areas on alluvial soils. This
tree can be found from Kenya in the north to KwaZulu Natal in the
south. It is a prominent feature in the lowveld region of South
This tree is popular amongst birds for nest building as the thorns
add extra protection against predators such as snakes. Young branches
and leaves are eaten by elephant and the leaves and pods are eaten
by giraffe and vervet monkeys. Monkeys and grey louries also eat
the flowers. The gum and green seeds are eaten by baboons. Insects
such as bees are attracted by the yellow colour and sweet scent
of the flowers and perform a pollination role.
The wood is hard, heavy and a suitable general purpose timber but
it should be seasoned before use otherwise it is likely to crack.
The main stems and larger branches are used to fence out hippo from
fields on the Pongola floodplain and the timber is reputed to be
used for boxwood. Medicinally the bark is used for treating fevers
and eye complaints.
Early pioneers thought that this tree caused a fever since people
travelling or living in the areas where it grew contracted a bad
fever. They therefore associated the fever with the tree. This however
was erroneous as the swampy places where fever trees grow are also
ideal breeding grounds for mosquitoes, which carry malaria. Thus
through these early settlers the myth was born and the plant acquired
its name as the fever tree.
Growing Acacia xanthophloea
The fever tree is an exceptionally attractive tree and is often
used to decorate gardens and urban landscapes. Its contrasting bark,
feathery foliage, and architectural attributes make it an eye-catcher
and thus suitable as a focal point in a landscape. A fast growth
approximately 1.5 m per year under ideal conditions make this plant
a good candidate for gardeners and landscapers who want quick results.
This plant has root nodules containing nitrogen fixing bacteria
as do most members of the Mimosaceae family and these play an important
role in the nitrogen enrichment of soils which then has a positive
impact on the growth of plants around the fever tree. The dappled
shade underneath the canopy is ideal for smaller plants which require
protection from the full brunt of the suns rays but still require
The fever tree is relatively easy to propagate. Before sowing,
the seed should be soaked in hot water overnight. This causes the
seeds to swell and usually by the next morning they are ready to
be sown. Seed can be sown in seedling trays using a well drained
seedling medium and then covered lightly. When the seedlings reach
the two-leaf stage (approx. six to eight weeks after sowing) they
should be transplanted from seedling trays into nursery bags, taking
care not to damage the long taproot. Seedlings and young trees transplant
well. Seed and young growing plants are available at selected seed
stockists and nurseries respectively.
Due to its mature dimensions it is recommended not to plant it
close to buildings. This tree can tolerate moderate frost and can
often be seen in cultivation in the cooler areas on the highveld
such as certain parts of Johannesburg and Pretoria.
Acacia xanthophloea belongs to the pod bearing family Fabaceae.
There are 40 species , subspecies and varieties of Acacia represented
in South Africa. Many species such as the fever tree have leaflets
which fold up at night. A special feature of this family is the
pulvinus which is a conspicuous thickening at each petiole and petiolule
base which allows the leaves to close at night and also during extreme
heat. Stipules (or a stipular scar) are always present and are often
modified into thorns or spines as is the case with the fever tree.
The genus Acacia is mostly confined to Africa where almost
all have stipular spines or recurved thorns. It is also found in
Australia where most are without thorns. Acacias are conspicuous
, particularly in drier areas, becoming dominant in many vegetation
types and are important fodder trees with useful wood, gum, and
bark. Acacias are also host to many butterfly species which have
specialised in feeding on the flowers pods or leaves.
- Coates Palgrave, K. 1983 Trees of Southern Africa. Struik: Cape
- Johhson, D. & Johnson S.1993 Gardening with Indigenous Trees
and Shrubs. Southern Book Publishers (Pty) Ltd.
- Smit, N. 1999 Guide to the Acacias of South Africa. Briza: Pretoria
- Pooley. E 1993. The complete field guide to Trees of Natal,
Zululand & Transkei. Natal FloraPublications Trust: Durban.
- Trendler, R. & Hes, L. 1994. Attracting Birds to your Garden
in southern Africa. Struik Publishers (Pty)Ltd.: Cape Town.
- Venter, F & Venter J. 1985 Making the Most of Indigenous
Trees. Briza Publications:Pretoria.
- Van Wyk, B, & van Wyk, P. 1997 Field Guide to Trees of Southern
Africa. Struik: Cape Town.
Andrew Hankey & Marc Stern
Witwatersrand National Botanical Garden