This widespread dune plant is edible and also performs an important
role in stabilizing the sand, enabling the dune to develop into
a friendly environment for other plants.
This is a spreading shrub with dark green, sessile, glistening leaves.
The sheen is caused by small, shiny, water-storage cells that cover
the surface of the leaf. The small, 4-petalled, yellow flowers are
situated in groups of 3-5 in the upper leaf axils. They flower from
August to November. The fruits are thickly 4-winged.
Found on coastal sand dunes from southern Namibia to the Eastern
Derivation of name and historical aspects
The genus name is derived from the Latin word, tetragonus
which means 4-angled, relating to the fruit, and decumbens
means prostrate with tip rising upwards.
early colonizer of moist sand dunes, it is an extremely valuable
plant for stabilizing moving sand. It acts as a seed-trap and also
provides organic matter that enables other species to grow on the
dunes. The accumulation of plants matter such as that of Tetragonia
decumbens, and the subsequent establishment of other plants, enable
dunes to develop from foredunes to rear dunes that are stabilized
by increasing plant growth. The four-angled fruits are easily blown
about by the wind, aiding their dispersal.
Apart from their very important use to stabilize moving sand, the
plants are also edible. The new growth, which occurs during the
rainy season, is the best to use. The tops and leafy stems are harvested
and must be thoroughly washed to remove the clinging sea sand. They
are then boiled and because the flavour is rather bland, one of
the traditional Cape seasonings, in the form of Oxalis pes-caprae,
and a blob of butter added to the dish make it more palatable. The
texture of the resulting spinach is somewhat grainy, but not unpleasant.
Raw leaves have a somewhat salty taste. It is thought that with
appropriate selection, the plant could be domesticated, yielding
a crop similar to its close relative, New Zealand spinach, Tetragonia
Growing Tetragonia decumbens
The easiest method of growing this plant is to pull up branches
from the sand and separate pieces with roots attached as cuttings.
These can be planted directly in situ into well-drained, sandy soil,
which must be kept slightly moist until the plants have established
Pests and diseases: The leaves are occasionally chewed by
insects, but are more likely to be damaged to a very small extent
by strong winds and sandblasting. Trampling also causes damage.
- Adamson, R.S. & Salter, T.A. (eds). 1950. Flora of the
Cape Peninsula. Juta, Cape Town & Johannesburg.
- Manning, J.P. & Goldblatt, P. 2000. Wild flowers of the
fairest Cape. Red Roof Design & the National Botanical
Institute, Cape Town.
- Smith, C.A. 1966. Common names of South African plants. Memoirs
of the Botanical Survey of South Africa No. 35.
- Van Wyk, B-E. & Gericke, N. 2000. People's plants. A
guide to useful plants of southern Africa. Briza Publications,
Harold Porter National Botanical Garden