Sarcostemma viminale subsp. australe

Common name: Caustic Bush

Family: ASCLEPIADACEAE

Sarcostemma viminale subsp. australe beginning to flower. Photo: D. Blumer.View image slideshow

Origin of Scientific Name

Sarcostemma – derived from the Greek sarcos, flesh and stemma, crown or garland; referring to the fleshy stamina corona of the flowers.

viminale – long, slender shoots

Description

This species is a shrub or climber that grows from 0.3 - 5 metres high. The stems are sprawling to erect, silvery-green and produce copious amounts of milky exudates when cut or broken. Flowers to about 0.8 cm long, starry, whitish to pale yellow, on stalks to about 0.6 cm long. Inflorescence terminal in 2-10 flowered clusters, rarely profuse.

Distribution

The ssp. australe is endemic and mainly found associated with red lateritic soils of rocky sites where it commonly grows in rock crevices and sandy soils over sandstone or limestone. It is widely distributed in Western Australia from the Central West Coast, Kimberley, Ningaloo, Pilbara and Shark Bay. Refer to the distribution map for this species via the Department of Parks and Wildlife's FloraBase online herbarium.

Flowering Season

January to November

Cultivation/Propagation

It adapts to cultivation in semi-arid, arid and temperate regions but can be slow to establish. Plants require warm to hot sites which receive plenty of sunshine and soils which are very well drained. They are well suited to cultivation in containers and rockeries. Propagation is most successful from cuttings. Cuttings of young but moderately firm stem growth strike readily. It is best to allow the base of the cutting to dry out for about 24 – 48 hours (wrap in dry newspaper) before putting them into the propagating mix. Care needs to be taken as the latex exuded from the stem may cause irritation.

Notes

Sarcostemma is one of the few true succulents found in Western Australia. Such plants have evolved to survive in dry, arid or harsh environments, store water in their leaves, stem or roots and can hold their form during extended dry periods without any severe loss of leaves or condition.

View in Kings Park

This species can be seen in the Mulga beds at the entry to the Western Australian Botanic Garden and in the desert beds within the Roe Gardens. Refer to map.