CYPHOSTEMMA SEGMENTATUM IN HABITAT AND CULTIVATION.
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 The woodland frequented by Cyphostemma segmentatum consists mainly of Acacias, Commiphoras and Euphorbias. Commiphoras are well represented particularly Commiphora schimperi and Commiphora viminea. |
SUMMARY.
Cyphostemma segmentatum is amongst the most beautiful of South Africa’s caudiciform plants. The caudexes sprout annual stems adorned with evenly spaced holly-like bluish green succulent foliage. The plants occur mostly in arid mountainous country in South Africa’s Limpopo Province and are probably best represented in the rugged western foothills of the Transvaal Drakensberg, in Sekhukhuneland.
The newsletter concerns an account of these Cyphostemmas in habitat and details about their cultivation and propagation. This species is particularly useful for ornamental containing particularly in terracotta pots which display the leaves to good effect.
NEWSLETTER.
Cyphostemma segmentatum is well represented in the western foothills of the Transvaal Drakensberg near Penge. This is a rugged remote area and part of Sekhukhuneland which is rich in endemic plant species. C. segmentatum is best represented on boulder strewn mountain slopes where it grows in deciduous woodland consisting mostly of various Acacia and Commiphora species.
The plants are usually encountered in stony loamy areas with a light covering of annual and perennial grasses. These places are grazed by livestock belonging to the local people who live in villages in the valleys. The herbs and grasses are kept short by the grazing animals and these conditions ideally suit the requirements of the Cyphostemmas. In habitats higher up the mountains where the vegetation is much more dense and not grazed, the numbers of C. segmentatum decline considerably. There are far fewer niches in the habitat for the plants to colonise since the Cyphostemmas require direct sunlight or lightly dappled shade in order to thrive.
THE SUMMER GROWING SEASON.
C. segmentatum starts to sprout leaves with the first good early summer rains which usually fall in October. In dry years the commencement of growth may only be in November. Each tuber usually sprouts 1 – 2 annual stems which are well branched in older plants. They are usually in flower within a few weeks after the tubers have sprouted and the cluster of small pale yellow flowers are conspicuous to pollinators. Pollination seems to be mainly effected by wasps and also possibly flies. At the time the plants are in flower the surrounding landscape is still brown and sere after the winter drought. The Cyphostemma leaves and flowers stand out from the otherwise drab background.
The early summer in November and the first half of December 2007 provided ideal growing conditions for the C. segmentatum near Penge. A few soaking rains in late October and early November resulted in excellent flowering on the mountain slopes and many Cyphostemmas were in full fruit when abundant rains fell in the second half of November and early December. Good widespread seed production like this only happens about once a decade and the resultant seed bank lasts for a number of successive seasons as some seeds take several years to germinate.
C. SEGMENTATUM IN THE MODERN SEKHUKHUNELAND ENVIRON-MENT.
Much of the flora in Sekhukhuneland has either adapted to heavy grazing by livestock or become commensal with grazing. C. segmentatum is one of the many species of bulbous and caudiciform plants that has fared well. The grazing keeps the hillsides free from accumulations of dead grass and reduces the level of competition some caudiciforms have from other common plants. This is particularly true for the development of C. segmentatum seedlings. They have expanded into areas littered with small rocks and pebbles which would otherwise be too full of grass for successful germination of the Cyphostemma seeds.
Sekhukhuneland is an area which lies in the rain shadow of the Transvaal Drakensberg and is subject to prolonged and frequent droughts. With exceptional rainfall such as that experienced in the summer of 2007/2008 the countryside comes to life with an astonishing richness of geophytic plants. The Cyphostemmas may even be seen in the vicinity of rural villages in the most arid and overgrazed places during years of abundant and widespread rains.
CULTIVATING CYPHOSTEMMA SEGMENTATUM.
C. segmentatum grows well in large containers or rockeries. It is particularly useful for planting in large terracotta containers in hot sunny positions where little else feels at home. The tuber should be planted about 6 – 12 cms below the surface of the soil. The grey leaves are very effectively displayed amongst large reddish brown or dark brown boulders arranged at different levels on the surface of the container. Terracotta containers with a high back are particularly useful as a backdrop for the fresh powdery blue grey leaves produced in the early spring.
The plants grow well when exposed to natural rainfall but they should be thoroughly watered occasionally when it is very dry in summer. During the winter dormancy period April to September the pots should be kept dry. They should however be well soaked twice during the second half of September to encourage growth in October, the main months when flowers are produced and pollination occurs.
Plants are usually well pollinated when grown close together in open sunny places. The seeds mature in January and February and should be harvested as they start to turn red. They should then be tightly rubbed between two pieces of equal sized fly screen netting to remove the pulp. Afterwards they are best rinsed on one of these pieces of netting under a strong fine spray of water and afterwards left to dry in the sun.
C. segmentatum seeds should be sown in deep pots, each seed 4 – 5 cms apart. A coarse gritty medium with some sandy loam mixed in works well for germinating seeds and growing the young tubers. Seeds germinate erratically but well when exposed to natural rainfall.
C. segmentatum seeds are notorious for germinating slowly and irregularly. One method that speeds up germination is to leave the seeds exposed to weathering in the sun for a few weeks. They generally germinate best from the second and third seasons after they were set.
Photographs by Connall Oosterbroek
