Curtisia dentata is a handsome, evergreen tree with beautiful
foliage that looks good throughout the year. It has great potential
as a garden tree, an evergreen hedge and a timber tree.
medium to tall evergreen tree, 2-12 m and up to 20 m in height.
The bark is smooth and grey or cinnamon-coloured in young specimens
but it becomes rough, dark brown to black and deeply square-fissured
with age. The leaves are simple, 25-100 x 19-76 mm, egg-shaped with
pointed tips and coarsely toothed edges, and are arranged in opposite
pairs. The upper surface is smooth and dark glossy green whereas
the undersurface is grey-green with conspicuous veins. The undersurface
of the leaf, the leaf stalk and the twigs are all covered with small,
reddish hairs. Very young growth is velvety to the touch and bronze-gold
The flowers are inconspicuous, not very attractive nor are they
scented. They are small, drab cream- or fawn-coloured and velvety
and appear in much-branched sprays at the ends of twigs in spring-summer
(Oct.-Mar.). They are often parasitized so that only a few produce
fruit is a small, rounded to oval, fleshy berry, about 10 mm in
diameter. They generally appear 6-10 months after flowering (May-Oct),
and are white, or white tinged with pink, sometimes becoming red,
and crowned with the remains of the calyx. The fruits contain a
four-chambered nut, one seed per chamber, although not all four
seeds are always formed. Fruits are edible but bitter. They remain
on the tree for a long time and can be very decorative.
The assegai grows in most of the forests in southern Africa and
Swaziland, from sea level to 1 800 m. It ranges from the Cape Peninsula
through the forest patches of the eastern Western Cape to the forests
of the Knysna region, the Eastern Cape, KwaZulu-Natal, Mpumalanga,
Limpopo and Swaziland. In the forest it is usually found in climax
forest and grows into a tall tree with a clean, unbuttressed bole.
It also grows on grassy mountain slopes and in coastal scrub forest
where it is a small bushy tree.
Curtisia dentata trees are at their best in medium-moist
forest, where they are found growing with Podocarpus latifolius
(yellowwood) and Olea capensis (black ironwood). In the dry-type
forest they are generally smaller, and in moist forest they are
comparatively rare. They are also present in coastal and montane
forests but do not reach as large a size as in the forests of the
plateaux. It is never found in pure communities nor is it ever dominant
or even co-dominant. Curtisia is capable of living in the
dense shade of a natural forest, but young trees grow faster under
higher light intensities.
Curtisia dentata retains its leaves for 2-4 or more years
and does not create much leaf litter. It is storm-firm, because
it is a deep-rooted species, it does not form a heavy crown and
has remarkably tough branches that are rarely broken by severe winds.
The flowers are odourless and secrete no nectar. The honey-bee
does not visit the flowers for pollen, nor do any other insects
pay any serious attention to them. Pollination experiments and observations
by Phillips (1928) have shown that the species is almost entirely
self-pollinated, but cross-pollination by wind may take place. Flowers
are produced every year, and fruits are usually formed 6 to 10 months
later, although some years are bad years when the flowers are diseased
by a gall-forming organism and fruit formation is very poor.
The fruits are bitter and are eaten by birds, bats, monkeys, baboons
and wild pigs. The lourie and the bush dove appear to be the main
agents of dispersal of the seed, but most of the seeds actually
fall to the ground at the base of the parent. About 50% of the viable
seeds that drop actually produce seedlings. In nature, the seeds
normally germinate 6 to 12 months but never more than 15 to 18 months
after the fruits drop, the delay probably being due to the time
taken for the corky pericarp and the hard nut that encloses them
Turkey-tail bracket fungus attacks dead trunks and branches.
Uses & cultural information
The timber of the assegai is good, strong and durable and has been
exploited since the earliest colonial days, particularly for wagon-making-so
much so that thousands must have been felled and a well-grown mature
tree is still uncommon in our forests. The timber is reddish, turning
red-brown with age and somewhat resembles mahogany, and is extremely
tough, strong and elastic with a fine grain. As dry assegai shrinks
less than most other woods, it made the best spokes of any Cape
wood, and was also valuable for felloes (curved strips joined together
to form the rim of a wheel). It was also used by the Voortrekkers
to make axles for their wagons, and was popular too for other wagon
parts, tool handles, furniture, rafters and flooring.
The bark, twigs and leaves were once used for tanning leather.
The bark is in great demand for traditional medicine, and is used
to treat stomach ailments, diarrhoea and as a blood purifier and
aphrodisiac. It is used only in special mixtures because it is now
too scarce to be used in most mixtures.
Derivation of the name & historical information
Curtisia is a genus of only one species. It belongs in the
Cornaceae (dogwood family), a small family of about 15 genera most
of which occur in the temperate parts of the northern hemisphere.
The most well-known genus is Cornus, the decorative dogwoods.
Curtisia is the only southern African member of the family,
and has no close relatives in southern Africa. The family gets its
name from its typically hard timber, from the Latin cornu
meaning horn, alluding to the hardness of the wood.
is named in honour of William Curtis (1746-1799), founder of Curtis's
Botanical Magazine, first published in 1786 and still going today.
The specific name dentata is Latin for toothed, and refers to the
The common name assegai, is derived from the Arabic name azzaghayah,
that was adopted by the Portuguese, with various modifications of
spelling, and taken over by the early Dutch writers. This name was
already recorded, in modern spelling, in 1625, and in 1652, Van
Riebeeck referred to hassegaayen used by the natives for
spears and bows. It is commonly supposed that Curtisia dentata
got this common name because the shafts of assegais were once
made of the wood, as Thunberg wrote in 1774, 'The Assagay tree is
used for poles of wagons and as shafts for the Hottentot's javelins'
(Palmer & Pitman 1972). But some dispute this and think that
the name is from the resemblance of the leaves to an assegai blade
and that the assumption that the wood was used to make assegais
comes from the name-something of a chicken-and-egg situation, which
remains unresolved. Nevertheless, this name was first recorded for
Curtisia dentata in 1662 in Wagenaer's forest survey which
mentions hazegaijen boomen hout (Smith 1966). To add a touch
of romance to the debate, trees of this family have an ancient connection
with spear-making. The shaft of the spear that Romulus flung towards
the Palatine Hill when marking the boundaries of Rome is supposed
to have been of a dogwood, popularly known as the cornelian cherry.
By tradition, the Trojan Horse was also carved from this tree. So,
trees of this family have had quite an impact on history, providing
spears for Roman soldiers and possibly also African warriors, and
shaping the history of Troy, and providing wood for the wagons that
opened up the interior of South Africa.
Growing Curtisia dentata
assegai is handsome, fast-growing and easy to grow. It grows into
a tall shapely, densely-leafy evergreen tree with a rounded crown
that looks good all year round. It can be grown in full sun to light
shade. In full sun it becomes bushy, and makes an attractive, tall,
leafy hedge or screen. Its roots are non-invasive and it has a long
lifespan, i.e. 30+ years. It is a good tree for gardeners wishing
to attract birds to their garden.
For best results plant it in deep, fertile soil with plenty of
compost and water generously for the first 2 to 3 years. Apply compost
at least on an annual basis, and a general fertilizer in spring.
Although it prefers a warm, well-watered climate, once established
it will withstand moderate drought. It is also sensitive to frost,
young plants being killed and older plants temporarily defoliated.
Established plants should survive moderate frost.
Curtisia dentata is best propagated by seed. Remove the
fleshing covering of the berry and sow the nut when fresh, covered
lightly and keep warm and moist. Germination takes 3 to 4 weeks.
Seedlings are vigorous but highly susceptible to injury from drought,
high surface soil temperature, frost and damping off fungi. They
are thus best kept moist, but not wet, in light shade and protected
from frost and full sun. The trays should be treated with a fungicide
that combats damping off. Young saplings are also very sensitive
to bright light, full sun will scorch the foliage and could even
kill the young plant. Saplings are best grown in light shade; deep
shade will also result in healthy plants but slower growth. Saplings
are also sensitive to frost.
Cuttings do not strike adventitious roots readily, but cut stumps
coppice freely and the roots give off suckers.
References and further reading
- Coates Palgrave, M. 2002. Keith Coates Palgrave Trees of
southern Africa, edn 3. Struik, Cape Town.
- Germishuizen, G. & Meyer, N.L. (eds). 2003. Plants of southern
Africa: an annotated checklist. Strelitzia 14. National
Botanical Institute, Pretoria.
- Palmer, E. & Pitman, N. 1972. Trees of southern Africa.
Balkema, Cape Town.
- Phillips, J.F.V. 1928. Curtisia faginea Ait. ("Assegaai"):
an ecolgical note. Transactions of the Royal Society of South
Africa 17: 19-42.
- Smith, C.A. 1966. Common names of South African plants. Memoirs
of the Botanical Survey of South Africa No. 35. Department
of Agricultural Technical Services, Pretoria.
- Van Wyk, B-E., Van Oudtshoorn, B. & Gericke, N. 1997.
Medicinal plants of South Africa. Briza Publications, Pretoria.
Kirstenbosch National Botanical Garden