
This beautiful tree is the most common naturally occurring
acacia in the Witwatersrand National Botanical Garden. It may reach
up to 14m and has an irregular, spreading crown. In some habitats
it remains as a shrub. One of the most attractive features of the
tree is the foliage which is bright green and feathery looking.
The leaves are drooping which gives the canopy a lovely soft look.
The name Acacia is derived from "akis
" meaning a point or barb and caffra was a epiphet frequently
bestowed on plants from the eastern parts of South Africa in previous
centuries. The word caffra in Hebrew means "person living
on the land".
The Acacia caffra occurs naturally in a wide
variety of habitats from coastal scrub to bushveld and highveld
grasslands. The distribution appears to be slightly patchy with
the species occurring in the four northern provinces; the coastal
areas of Kwazulu Natal and the Eastern Cape and in some areas of
the Western Cape. Another interesting feature of the tree is its
tolerance of low soil pH which occurs where the soils are sandy
and the rainfall is high. The Acacia caffra is able to withstand
fire, which is important in areas such as grasslands and savannas
where fire forms an integral part of the ecology.
The
tree is deciduous and is one of the first to shoot in spring. The
new leaves are particularly pretty, being a soft, fresh green. The
flower spikes are creamy white and sweetly scented. They appear
from September to November with the main flowering occurring in
October. The flower spikes are large and conspicuous and make a
lovely show against the backdrop of the new leaves. They are followed
by narrow, straight, brown seeds pods.
The Van Son's Playboy (Deudorix vansoni) and
Pennington's Playboy (D. penningtoni) butterflies breed in
galls on the branches of the tree. The wood is dense and hard and
beautifully grained. The foliage enjoyed by game and stock. The
common hook-thorn is used traditionally for many purposes such as
fencing posts, tanning and the beautiful rootwood is highly valued
by Xhosa women for tobacco pipes. It is also used medicinally and
is considered a lucky tree in traditional African beliefs.
Growing Acacia caffra
The trunk is very often crooked which gives the tree
wonderful character in a garden. It is frost and drought resistant
and has a growth rate of about 700mm - 900mm per year. Like other
Acacia species the common hook-thorn throws a light shade
which allows enough light through to enable lawn to grow beneath.
Acacia caffra has a stately shape and looks very elegant
in a sweep of lawn. It responds well to pruning. Avoid planting
near paving or buildings as it reportedly has an aggressive root
system.
It grows easily from seed. The seeds need hot water
treatment before they will germinate. Simply pour hot water over
them and allow to cool. You will see if this has worked as the seeds
will begin to swell as they absorb water. Do not leave them in the
water for longer than 24 hours or they will start to deteriorate.
It is best to sow directly into black bags as the taproot is long
and is sensitive to transplanting.
References:
- Henning, G.A, Henning, S.F et al. 1997. Living Butterflies of
Southern Africa, Vol. I. Umdaus Press. Pretoria.
- Pringle, E.L.L., Henning, G.A., Ball, J.B. (eds) 1994. Pennington's
Butterflies of Southern Africa. 2nd Edition. Struik. Cape Town.
- Smit, N. 1999. Guide to the Acacias of South Africa. Briza Publications.
Pretoria
- Thomas, V and Grant, R. 1998. Sappi Tree Spotting, Highveld
and the Drakensberg. Jacana Education. Johannesburg.
- Van Wyk, B and van Wyk, P. 1997. Field Guide to Trees of Southern
Africa. Struik Publishers. Cape Town.
- Venter, F and J-A. 1996. Making the most of Indigenous Trees.
Briza Publications. Pretoria.
Alice Aubrey
Witwatersrand National Botanical Garden
September 2001
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