African Wildlife & Environment Issue 81

GARDENING FOR BIODIVERSITY

Here at home, the pale orange to deep red, tubular, pendulous flowers of the nasty invasive alien Chandelier Plant Bryophyllum delagoense superficially resemble those of C. orbiculata . This erect, succulent shrublet is often mistaken as indigenous but it hails from Madagascar. Besides producing abundant seeds, B. delagoense reproduces rapidly when pieces break off, fall to the ground and strike root to form new plants, often forming dense stands in the process. In fact, this problem plant has been classified as a weed and allowing it space is actually a criminal offence. Unfortunately C. orbiculata plants are, understandably, sometimes not popular with farmers. When the veld is poor, often as a result of overgrazing, their livestock resort to eating the fleshy leaves which contain various toxins. Affecting the nervous and muscular systems, poisoning can result in paralysis and is also characterized by contractions of the muscles, hence the popular name of krimpsiekte (shrinking disease).This has, in turn, given rise to another, uncomplimentary, common name for the plant of Krimpsiektebos. Often fatal, this ‘cotyledonosis’ can affect virtually any type of farm animal from chickens to horses, though goats and sheep have been most commonly afflicted. Even dogs eating meat from poisoned animals have developed the symptoms and this would probably also apply to

easy source of income. However, to be sure of propagation success when taking cuttings, it is best to leave them for a week or so to form ‘scabs’ at the cut ends and then to plant them in moist, clean sand. Although a slower method of propagation, C. orbiculata can also be grown from the many minute seeds contained in the small pods. After the seeds have been sown, they should be watered with a very fine spray to avoid disturbing them.

Cotyledon orbiculata featured on a South African stamp.

Being so easily cultivated, it is not surprising that C. orbiculata has become a popular garden plant in warmer areas all over the world. It is now so well settled in other countries that, some years ago, overseas gardeners may have been surprised, when receiving correspondence from South Africa, to see an image of ‘their’ familiar garden plant on one of our previous postage stamps. However, easy propagation and the absence of its natural enemies has resulted in C. orbiculata escaping from gardens and becoming invasive in many parts of Australia, New Zealand and in California, where it has the alternative common name of Round-leafed NavelWort.

Gardeners can easily confuse the flowers of the invasive alien Bryophyllum delagoense with those of the indigenous Cotyledon orbiculata.

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