Gardenia thunbergia is a beautiful flowering shrub or small
tree, with showy, heavily perfumed flowers and decorative fruits.
is an evergreen shrub or small tree, 2 to 5 m in height, with a
smooth, whitish, usually straight main stem up to 250 to 300 mm
in diameter, and short, rigid branchlets. The leaves are carried
in whorls of 3 or 4 crowded near the ends of the branchlets. They
are a glossy light green, hairless, softly to thinly leathery and
conspicuously veined. Simple with an entire, wavy margin, variable
in size, up to 140 x 60 mm but usually smaller, mostly oval, tapering
abruptly to a rounded or blunt tip while the base tapers onto the
flowers are large, showy, creamy white and heavily perfumed, particularly
at night. They open from elegantly furled creamy-green buds. The
flowers do not turn yellow as they age on the bush. The corolla
is a 70-120 mm tube with 8 large lobes spreading to ± 80
mm in diameter. Flowers are produced abundantly during summer (October
to March), peaking in late summer (January to March).
The fruits are hard and woody, and heavily fibrous inside, and
where not being browsed by large antelope, can remain on the bush
Each fruit is egg-shaped, greyish green, 50-75 x 35 mm, when mature
roughly dotted with whitish encrustations.
Moths are attracted to the flowers and are probably the pollinators.
The fruits do not burst or split open, or drop, and can remain on
the bush for years. They are adapted to being eaten by elephants,
large antelope and buffalo, and the seed coats are tough enough
to pass through their digestive systems unscathed. Unless man intervenes,
the seeds will not be released from the fruits and dispersed unless
these animals eat them. Harvesting Gardenia thunbergia seed
is hard work. The secateurs we use to cut off the fruits are blunted
by the end of the process, not to mention our hands that are also
worn out. We have to use hammers, or any heavy, blunt instrument
we can find to break the fruits open, and nails and heavy duty spoons
to scoop the seeds out. It is heavy, laborious, unpopular work!
thunbergia occurs in a strip up the eastern coast of South Africa
from near Grahamstown in Eastern Cape to Kosi Bay in the north of
KwaZulu-Natal. It occurs primarily in evergreen forest and forest
margin, occasionally in woodland and bushveld.
Derivation of the name & historical aspects
The genus Gardenia was named in honour of Dr Alexander Garden
(1730-1971) a Scottish physician who practised in South Carolina,
USA, and a correspondent of Linnaeus. This species was named after
Carl Thunberg, pupil of Linnaeus and a well-known 18th century botanist
and traveller in South Africa. The Afrikaans common name buffelsbal
means buffalo testicles, a reference to the shape of the fruit.
The Zulu name umvalasangweni means the back-gate closer and
refers to the fact that it and other spiny shrubs and trees are
used as the gates for cattle kraals.
Gardenia thunbergia was the first of the South African gardenias
to be known to botanists, and was introduced to Kew in 1773.
The gardenia family (Rubiaceae) is a large, cosmopolitan family
containing 630 genera and 10 200 species. This family's greatest
claim to fame is the South American quinine tree, Cinchona,
whose bark yields quinine, the first drug ever used to treat malaria.
Coffee, Coffea arabica, is also a member of this family. In South
Africa, the family is best known for its decorative flowering trees
and shrubs: Gardenia, Rothmannia, Hyperacanthus, Alberta
and Burchellia. The genus Gardenia consists of approximately
60 species that occur in tropical and warm parts of the Old World.
Six species are found in South Africa, in all provinces except the
Northern and Western Cape. Gardenia thunbergia can be readily
distinguished from other similar species growing in South Africa,
but is possibly often confused with other species growing in Zimbabwe
and further north. It may be distinguished from G. resiniflua,
the gummy gardenia, by its much larger fruits, and from G. volkensii,
the Transvaal or savannah gardenia, by the fact that its fruits
are not ribbed. G. cornuta, the Natal gardenia, which has
un-ribbed fruits of similar size and shape can be distinguished
by the fact that its fruits are orange not grey. G. ternifolia
(= G. jovis-tonantis) the large-leaved Transvaal gardenia, has short
hairs on both leaf surfaces, which are rough to the touch, whereas
G. thunbergia leaves are smooth and hairless. Another distinguishing
feature is that G. thunbergia flowers do not age yellow as
many of the other species do. Hyperacanthus amoenus (= Gardenia
amoena) the spiny gardenia, has paired spines at right angles to
the next pair, and pink tinged white flowers. Gardenias are also
quite similar to rothmannias, but an easy way to distinguish them
is by their flowers: gardenia flowers are tubular with many petals,
whereas rothmannia flowers are funnel shaped with only five petals.
Roots are widely used in Africa to treat skin diseases, and
skin lesions caused by leprosy. The roots are also used as an emetic
against fever. The rootbark is used as an emetic for biliousness,
and to treat gall bladder problems. The roots and leaves are used
in various parts of Africa to treat syphilis, and the latex is used
as a purgative. The wood is heavy, dense and extraordinarily hard,
a pleasing yellowish colour, and it presents a high lustre when
polished. It also has the unusual ability to bend without breaking,
but its use is limited because it is difficult to find large pieces.
It is used for making buttons, tools, clubs, yokes, axles and implement
handles. The fruits would make novel Xmas baubles.
Growing Gardenia thunbergia
Gardenia thunbergia is easy to grow, although it is slow-growing.
It does best in sun or semi-shade, in slightly acid, light, well-drained
soil with plenty of organic matter added and regular deep watering.
Mulch thickly and regularly. Although Gardenia thunbergia
is relatively slow growing and generally needs little pruning, it
may need to be pruned to keep it shapely, or in scale with its container.
Pruning should be done after flowering or just before the new growth
appears. Although it is moderately drought tolerant, drought stress
can cause buds to fall before opening. Gardenia thunbergia
is half hardy and should tolerate a winter minimum of -1°C
although young plants will require protection from frost. If you
notice yellowing of the leaves, this is usually due to a trace element
deficiency and can be corrected by feeding with a fertilizer that
includes trace elements.
It looks good as a specimen plant on a lawn, or as part of an informal
hedge or shrubbery, or planted beside a pond or a stream. It also
makes a good pot plant in a large container, its pale grey bark
and angular shape making it an interesting form plant, while the
flowers perfume the air. It is also suitable for bonsai.
It is easily propagated from seed, cuttings or truncheon cuttings.
Seed can be sown in spring to early summer, even in late summer
if your winters are mild. Germination should take 4-6 weeks. Cuttings
can be taken at any time of the year, but best results are obtained
in summer. Rooting of cuttings is best under mist, using a 100-120
mm piece of young (approx. 2 month old) growth with 2 or 3 sets
of leaves. There is no need to remove the leaves as it appears to
slow the rooting process down. Truncheon cuttings are best taken
in early spring, and placed in well-drained, sandy soil in a cool,
shady spot and kept damp but not wet.
- COATES PALGRAVE, K. 1977. Trees of southern Africa, edn
1. C. Struik, Cape Town, Johannesburg.
- GERISCHER, G.F.R., VAN WYK, W.J. & BRULHART, S. 1998. The
mechanical and physical properties of Gardenia thunbergia (white
gardenia) wood. South African Forestry Journal No. 182.
- GLEN, H.F. 1983. Gardenia thunbergia. The Flowering Plants
of Africa 47: t. 1863.
- HILTON-TAYLOR, C. 1996. Red Data List of southern African plants.
Strelitzia 4. National Botanical Institute, Pretoria.
- HUTCHINGS, A. 1996. Zulu medicinal plants, an inventory.
University of Natal Press, Pietermaritzburg.
- JOFFE, P. 2001. Creative gardening with indigenous plants.
A South African guide. Briza Publications, Pretoria.
- LEISTNER, O.A. (ed.) 2000. Seed plants of southern Africa: families
and genera. Strelitzia 10. National Botanical Institute,
- NEUWINGER, H.D. 2000. African traditional medicine. A dictionary
of plant use and applications. Medpharm GmbH Scientific Publishers,
- PALMER, E. & PITMAN, N. 1972. Trees of southern Africa.
Balkema, Cape Town.
- POOLEY, E. 1993. The complete field guide to trees of Natal,
Zululand and Transkei. Natal Flora Publications Trust, Durban.
Kirstenbosch National Botanical Garden