This attractive indigenous shrub may be found in a variety of habitats ranging from arid karoo, coastal dune bush, evergreen montane forest and wooded grasslands. On the Highveld, mainly grows in clumps of bush and rocky places, often in the shade of trees - it occurs naturally in the Witwatersrand National Botanical Garden where it is common and may be found in almost all areas. The natural distribution of the Grewia occidentalis ranges from the Western Cape up to Zimbabwe and Mozambique. This genus is named after Nehemiah Grew (1641-1712), an English physician. Occidentalis means from the west.
It is a scrambling deciduous shrub or small tree reaching up to 3m in height. Purple star-shaped flowers (measuring 1.5 to 3cm across) appear in summer (October - January), followed by distinctive four-lobed fruits (hence the common name cross-berry and four-corner). Fruits turns shiny reddish-brown to light purple when ripe (January - May) and may remain on the tree for long periods.
The leaves are alternate and simple with three distinct veins from the base. They are shiny deep green and may be slightly hairy on both surfaces. They are usually held in a horizontal plane towards the light.
Leaves are browsed by cattle, goats and game (black rhino, giraffe, nyala and grey duiker). Ripe fruits are relished by various birds such as louries, mousebirds, bulbuls and barbets as well as certain mammals (including man). Larvae of the rufous-winged elfin butterfly (Eagris nottoana) and buff-tipped skipper (Netrobalane canopus) feed on the leaves of this species.
In certain areas where the sugar content of the fruits is high, they are collected and dried for later use. The dried fruits are sometimes boiled in milk - a bush milkshake! Beer is also brewed from the ripe fruit in certain areas. Other human uses of this species include using the wood to make bows and spear shafts.
The cross-berry is an important species in
traditional medicine and is used for a variety of purposes. Bruised bark soaked in hot water is used to treat wounds. Pounded bark, used regularly as a shampoo, was believed to prevent hair from turning grey. Parts of the plant were used to treat impotence and sterility, and root extracts were used to help in childbirth.
Growing Grewia occidentalis
Grewia occidentalis makes a decorative garden plant which is both frost- and drought-hardy. It will grow well if well-watered and planted in good, composted soil. The cross-berry may be planted in either full sun or shade. The root system is not aggressive and can therefore be planted near buildings and paving. It is a "must-have" species in the garden to attract butterflies and birds.
This species is best propagated from seed. Studies have shown that seed which has passed through the gut of monkeys and baboons germinates better than those collected from a tree. This is due to the fact that the seeds chemical inhibitors have been broken down by the animal's stomach acids. However germination is generally fairly good - so perhaps it is not necessary to find a monkey to assist you with your propagation attempts!
- Pooley, E. (1993) Trees of Natal, Zululand and Transkei. Natal Flora Publications Trust : Durban.
- Thomas, V & Grant, R. 2000. Sappi Tree Spotting - Highveld. Jacana Education : Johannesburg.
- Van Wyk, B. & S. Malan (1988) Field Guide to the Wild Flowers of the Witwatersrand and Pretoria region. Struik Publishers : Cape Town
- Van Wyk, B. & P. van Wyk (1997) Field Guide to Trees of Southern Africa. Struik Publishers : Cape Town.
- Venter, F. & J. Venter (1996) Making the Most of Indigenous Trees. Briza Publications : Pretoria
- Heywood,V. H., Brummitt, R.K., Culham, M.A. & Seberg, RG, O. 2007.Flowering plant families of the world . Firefly books Ltd, Ontario,Canada.
Sharon Turner Walter Sisulu NBG November 2001Updated July 2008