Page 24 - Fourways Gardens August 2021

Nature

the sWeet thorn

B y Jam ES Clark E and m ary Bro adl E y ,
P H o t ogr a PHS B y Juli E Clark E -Ha v E mann
A tree with roots deep into our history.

t is not our national tree but it deserves In maturity, it is usually a nicely shaped tree Sweet thorns are at their showiest in
to be. It is probably our widest- with a domed evergreen crown reaching early summer when their crowns erupt
known and most prolific – the sweet at least thirty metres high, with the most with small, golden-yellow pompoms,
Ithorn or the soetdoringboom of the spectacular thorns. which attract several species of butterflies
old folksong. It has at least a couple of including ten that are totally dependent on
dozen names including cape gum, cape In younger trees, the thorns are slender, strong the mimosa-like blossoms. The blossoms
thorn tree, cockspur thorn, karoo thorn, white spikes up to 150 mm long with needle- metamorphose into knobbly crescent-
mimosa, white-thorn and, in Afrikaans, the sharp points. Needle sharp? Indeed, its thorns shaped pods that provide rich fodder for
doringboom, karoodoring, mookana and (or spines as they are properly called) have, for countless browsers, domestic and wild.
witdoring. In Ndebele, it is the isinga and in centuries, been used as sewing needles.
Tswsana, it’s the mookana or mooka, while The gathering in Australia deemed that
in Xhosa and Zulu it is the umNga. The sweet thorn is a hardy tree and because of the international rules of plant
relatively fast-growing – a pioneer plant classification, only Australia had the right to
So many names but there is only one that that will establish itself in most types of use the title ‘Acacia’. As a result, South Africa
was recognised by botanists, worldwide – soil from sand to clay and throughout was obliged to change the generic name of
the Acacia karroo. That’s been its scientific southern Africa, (except in montane all its 83 species of acacias.
name for generations. But, alas, a committee regions), as far as Central Africa.
of international botanists meeting in Overnight, Acacia karroo became Vachellia
Australia has deemed that South Africa In drier areas, sometimes picked over by karroo.
cannot use this name anymore. desperate browsers such as antelope and
goats, knee-high sweet thorns have found Likewise, the umbrella tree and the black
Local botanists are incensed. a way to survive – they bristle with a tangle thorn and the knobthorn, along with all the
of gleaming, closely-packed spines making rest of the acacias can no longer be referred
The sweet thorn has played an important them as unapproachable as an aggressive to as acacias.
role in South Africa’s development – in the porcupine. But, as the tree matures, such
country’s industrial development, in its dramatic defensive measures become less Three dozen botanists, led by South African
agricultural development . . . and even in necessary and the thorns tend to be shorter botanist Eugene Moll, claim the ruling goes
human health. and inconspicuous. against the normal rules of the system

Fourways Gardens • 22 • August 2021