The caterpillar grass, Harpochloa falx, is a wonderful garden
plant, which forms neat, dark green tussocks which persist throughout
the year and produce unusual 'toothbrush' flowers in summer. This
species, in common with a number of other indigenous tufted grasses,
provides a perfect foil for many South African plants such as aloes,
agapanthus, and red hot pokers.
Caterpillar grass is a densely tufted perennial, growing in tussock-like
form to about half a metre in height. The leaves are dark green,
coarse, narrow, and often in-rolled. They remain green throughout
the year in frost-free conditions. From September to April the one-sided,
sickle-shaped 'flowers' are produced on stalks about 750 mm long.
The species only occurs in Eastern Cape, KwaZulu-Natal, Lesotho,
Gauteng and Mapumalanga, usually in areas with a high rainfall.
It is common in the cool grasslands.
Derivation of name
The botanical name is derived from the interesting shape of the
inflorescence harpo means 'hook-like' and falx is
the Latin word for 'sickle'. The common name caterpillar grass
also refers to the flower shape.
Caterpillar grass is usually found in undisturbed, mountainous grassland,
on stony slopes in well-drained soil. In these areas it is common,
often forming dense stands. It withstands close grazing and trampling
better than other climax species such as rooigras (Themeda triandra).
As with most grasses. Harpochloa falx is wind-pollinated,
and copious amounts of pollen are produced by the exposed anthers
and carried by air currents to the feathery stigmas.
The toothbrush-like inflorescences are sometimes used in flower
This grass is highly palatable to livestock and game.
Growing Harpochloa falx
Ripe seed collected in the summer (November to January) germinates
easily in seed trays. Young plants can be planted out in spring
(or earlier in frost-free areas).
Alternatively, some nurseries sell young plants as 'plugs', which
can be planted directly into prepared ground and kept watered until
established. Thereafter, little attention is needed, other than
cutting back leaf mass at the end of winter. Once established, the
plants need very little water and do not appear to be susceptible
to disease or pests. (In spite of its common name it is not eaten
Harpochloa falx, with its rounded form, can either be grown
individually as 'specimen' plants, or grouped close together (30
cm spacing) to provide structure within a garden. The clumps of
grass are particularly striking when interspersed with plants of
contrasting growth form.
An effective planting in the Natal National Botanical Garden consists
of groups of caterpillar grass inter-planted with the blue squill,
- GIBBS-RUSSELL, G.E., WATSON, L., KOEKEMOER, M., SMOOK, L., BARKER,
N., ANDERSON, H.M. & DALLWITZ, M.J. 1990. Grasses of southern
Africa. Memoirs of the Botanical Survey of South Africa
- VAN WYK, E. & VAN OUTDTSHOORN, F. 1999. Guide to grasses
of southern Africa. Briza Publications, Pretoria.
Natal National Botanical Garden