Castor oil plant (Ricinus communis)

Castor oil plant is a medium to tall shrub. The whole plant is considered poisonous to humans and livestock.

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How does this weed affect you?

Castor oil plants grow vigorously in disturbed areas and out-compete native species for resources thus excluding them.

Toxicity

Castor oil plant is highly toxic to humans, capable of causing serious illness and death. The flowers, leaves and seeds are poisonous and eating only 2-8 seeds can be fatal. Ingestion causes a burning sensation in the throat and mouth, abdominal pain, bloody diarrhoea, fever, convulsions, and then respiratory and cardiac distress and failure. Temporary blindness may occur if the sap is squirted into the eyes.

What to do if poisoning occurs:

• If the patient is unconscious, unresponsive or having difficulty breathing dial 000 or get to the emergency section of a hospital immediately.
• If the patient is conscious and responsive call the Poisons Information Centre on 13 11 26 or your doctor.
• If going to a hospital take a piece of the plant for identification.

Where is it found?

Castor oil planct is native to Africa and Eurasia, it is common in disturbed areas and landfill sites. 

Distribution map

• NSW (image)

What does it look like?

Castor oil plant is a tall spreading shrub. Its stems are dull, pale green tinged with red. Leaves are divided into 7-9 lobes with toothed edges. 

References

Parsons WT and Cuthbertson EC (2001). Noxious weeds in Australia 2nd Edn, CSIRO Publishing, Collingwood.

James A and Harden G J (2014). Ricinus communis L., in PlantNET - The Plant Information Network System of The Royal Botanic Gardens and Domain Trust, Sydney, Australia. Available at http://plantnet.rbgsyd.nsw.gov.au. Accessed December 2014.

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Control

Due to the risk that castor oil plant poses to human and animal health, caution should be taken when attempting any control and removal of this weed. Wear protective clothing, gloves and eye protection before starting control work.

Herbicide options

See Using herbicides for more information.

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PERMIT 9907 Expires 31/03/2020
Glyphosate 360 g/L (Roundup®)
Rate: 1 part glyphosate to 50 parts water
Comments: Spray seedlings and coppice shoots.
Withholding period: Nil.
Herbicide group: M, Inhibitors of EPSP synthase
Resistance risk: Moderate

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PERMIT 9907 Expires 31/03/2020
Glyphosate 360 g/L (Roundup®)
Rate: 1 part glyphosate to 1.5 parts water
Comments: Cut stump/scrape stem application for saplings. Stem injection application large trees and shrubs.
Withholding period: Nil.
Herbicide group: M, Inhibitors of EPSP synthase
Resistance risk: Moderate

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2,4-D amine 625 g/L (Amicide® 625)
Rate: 340 mL per 150 L of water, or 3.4 L/Ha
Comments: Apply to young, actively growing plants.
Withholding period: 7 days.
Herbicide group: I, Disruptors of plant cell growth (synthetic auxins)
Resistance risk: Moderate

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Picloram 44.7 g/kg + Aminopyralid 4.47 g/L (Vigilant II ®)
Rate: Undiluted
Comments: Cut stump/stem injection application. Apply a 3–5 mm layer of gel for stems less than 20 mm. Apply 5 mm layer on stems above 20 mm .
Withholding period: Nil.
Herbicide group: I, Disruptors of plant cell growth (synthetic auxins)
Resistance risk: Moderate

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Triclopyr 600 g/L (Garlon® 600)
Rate: 1.0 L per 60 L of diesel
Comments: Basal bark application for plants up to 5 cm basal diameter. Cut stump application for plants with larger basal diameter.
Withholding period: Nil.
Herbicide group: I, Disruptors of plant cell growth (synthetic auxins)
Resistance risk: Moderate

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Biosecurity duty

The content provided here is for information purposes only and is taken from the Biosecurity Act 2015 and its subordinate legislation, and the Regional Strategic Weed Management Plans (published by each Local Land Services region in NSW). It describes the state and regional priorities for weeds in New South Wales, Australia.

Area	Duty
All of NSW	General Biosecurity Duty All plants are regulated with a general biosecurity duty to prevent, eliminate or minimise any biosecurity risk they may pose. Any person who deals with any plant, who knows (or ought to know) of any biosecurity risk, has a duty to ensure the risk is prevented, eliminated or minimised, so far as is reasonably practicable.

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Reviewed 2014