SA Orchids: Epiphytic Orchids

Mystacidium capenseIn the warmer and more humid parts of southern Africa there are a number of epiphytic orchids, which thrive on trunks and branches of trees and bushes. Unlike tropical Asian and American epiphytic orchids, which have often large and showy flowers (e.g. Cattleya or Cymbidium, that we see in our florist shops), the flowers of most southern African epiphytic orchids are small and inconspicuous. When searching for our indigenous epiphytic orchids it is sometimes a good idea to look out for their long, whitish roots creeping over the bark as these are often more noticeable than the rest of the plants. The leaves and stems are also not very noticeable, and leaves are even absent in a few species.

Where exactly do they occur?
Southern African epiphytic orchids are found in the southern coastal areas of the Western Cape, in the Eastern Cape and in KwaZulu-Natal, as well as in the inland areas of Mpumalanga and Limpopo. In the Western Cape, epiphytic orchids occur only from Swellendam eastwards: there are no epiphytic orchids near Cape Town. There are also no epiphytic orchids in the whole of the arid and semi-arid Karoo.

In which habitats do we find them?
Epiphytic orchids are found in a variety of forested habitats, ranging from hot subtropical lowland forest to cool high-altitude mist forest, frequently near the banks of rivers and streams. Epiphytic orchids are also found in hot and relatively dry scrubland and thorn-bush, and some species have even be found as epiphytes on succulent tree-like euphorbias! Occasionally, epiphytic orchids are also found growing epilithically on rocks.

The southern African epiphytic orchid flora and where it comes from
Most of the southern African epiphytic orchids belong to genera which are primarily tropical African in distribution, but range into our region with one or few species. Exceptions are the two primarily Asian genera Acampe and Oberonia, the pantropical genus Bulbophyllum as well as Mystacidium (see below). In total there are 56 epiphytic orchid species in 20 genera in southern Africa. This represents 12% of the total orchid flora of the region. Among these epiphytic orchids Angraecum (6 species), Mystacidium (7) and Polystachya (11) are represented comparatively well with more than five species. Mystacidium is the only epiphytic genus which is primarily southern African as most of its species and the highest diversity are found here. There is not a single genus endemic to our region.

How to grow southern African epiphytic orchids

Epiphytic orchids are normally easier to cultivate than terrestrial orchids and are therefore more popular as garden plants. To find out more about temperature, shading and watering requirements it is a good idea to look at the natural growing conditions of the plants. Epiphytic orchids can be grown in pots or hanging-baskets in a loose and well-drained substrate such as bark chips with some polystyrene granules added. Ordinary garden soil will quickly lead to the plants rotting. Plants can also be successfully grown by mounting them on slabs of cork oak or on the bark of living garden trees. In the growing season in summer the plants must be frequently watered, although the substrate must never be permanently wet (this is why plants mounted on bark normally do so well). Much less watering is needed in the dormant season in winter. Adequate air movement is necessary throughout the year.

It is highly illegal to take orchids from the wild, but epiphytic orchids can easily be obtained from specialist orchid nurseries - contact your local orchid society for their addresses. The easy-to-grow and also attractive Ansellia africana needs a hot place in your garden, with little shading. Aerangis, Angraecum, Cyrtorchis, Mystacidium and Polystachya are also good choices to start with, and require somewhat cooler and shaded sites.

Description : Hubert Kurzweil
February 2001

(Updated by Clare Archer, August 2010)

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