Calotropis procera (rubber bush) is a pest species in Western Australia (WA).
However, its legal status has been changed to Permitted (s11) for the whole of the state and it is not assigned to any control category for any local government area (Department of Agriculture and Food Western Australia (DAFWA) 2016).
Permitted organisms must satisfy any applicable import requirements when imported and may be subject to an import permit if they are potential carriers of high-risk organisms. Previously calotropis had a legal status of Declared Pest - Prohibited (s12).
Astron has recorded calotropis in the Pilbara region of Western Australia. Florabase also has records of it in the Central and Northern Kimberley region.
Calotropis is a shrub or small tree growing up to 4 m tall (DAFWA 2016). In December to January it gets very distinct purple and white flowers with five waxy petals in flower groups of up to 15 amongst the upper most leaves. It also has an inflated fruit pod which bursts when ripe and releases the seeds.
The recommended chemical control options for Calotropis are Picloram + 2,4-D amine, AccessTM or Picloram + triclopyr. For larger trees the cut stump or frill application method should be used applying undiluted chemical (DAFWA 2016). Mechanical removal by grubbing is only successful if the top 20 cm of the root is also removed.
For further information on weed control programs throughout Western Australia please visit our weed management page.
DAFWA 2016, Calotropis procera (Aiton) W.T. Aiton, https://www.agric.wa.gov.au/organisms/81064.