Cotyledon orbiculata has five varieties, based on differences in leaf and flower shape. The variability of leaf size, shape and colour is also influenced by the immediate environment. Selected forms in cultivation have been given names such as Elk Horns or Silver Waves.
Flowering time is mostly in winter from June-August, but in the winter rainfall areas such as the Western Cape, it is often in midsummer. The colourful, hanging, tubular/bell-shaped flowers are carried in clusters on the ends of an elongated flower stalk. They are mostly orange-red , but yellow flowering forms are also occasionally found (Ernst van Jaarsveld pers. comm.).
Distribution and habitat
Cotyledon orbiculata is widespread throughout South Africa, but is usually confined to rocky outcrops in grassland, fynbos and karoo regions. Black frost will damage the flowers if planted in an unprotected spot, but the plant itself will tolerate moderate frosts.
Derivation of name and historical aspects
The genus name Cotyledon comes from the Greek word kotyledon that means cup-shaped hollow, which refers to the leaves of some species. The species name orbiculata comes from the Latin word meaning round circle.
The name pig’s ears is derived from the oval shape of the grey-green leaves of some forms, which are very variable with a red or pale margins.
The genus Cotyledon consists of 10 species in South Africa. Other cotyledons recommended include C. woodii, C. velutina and C. papillaris. Another species, C. tomentosa, is a woolly shrublet with pretty red and yellow, bell-shaped flowers.
The brightly coloured flowers attract bees and birds, which feed on the nectar of the plant. The silver-grey leaves of some forms owe much of their attractive colouring to a powdery white coating which may assist in reflecting much of the sun’s heat to prevent excessive water loss from the thick succulent leaves.
This is a well-known medicinal plant. The fleshy part of the leaf is applied by many South Africans to soften and remove hard corns and warts. The Southern Sotho use a dried leaf as a protective charm for an orphan child and as a plaything. In the Willowmore District, the heated leaf is used as a poultice for boils and other accessible inflammations, earache in particular .
Van Wyk et al. (1997) report that a single leaf is eaten as a vermifuge and that the warmed juice can be used as drops for toothache or earache. They also report that the juice has been used to treat epilepsy.