(Tribulus terrestris)

Caltrop flower, photo: Jeff Abbas 2001

Status of caltrop in Tasmania

  • Caltrop is a declared weed in Tasmania under the Tasmanian Weed Management Act 1999. The importation, sale and distribution of caltrop are prohibited in Tasmania.
  • The legal responsibilities of landholders and other stakeholders in dealing with caltrop are laid out in the Caltrop Statutory Weed Management Plan.

What does caltrop look like?

  • Caltrop is a summer-growing annual herb with a prostrate (ground-hugging) growth habit. The stems are green to reddish brown, prostrate, to 2 metres long and covered in fine hairs. The leaves are opposite and of unequal size, each leaf consisting of 3 to 8 opposite leaflets, and covered in hairs. The flowers are yellow and short lived, lasting a single day. The fruit is a 1 cm diameter woody burr with spine, splitting into 5 wedge-shaped segments when ripe.
  • Seeds germinate in late spring and summer after rain. Flowering begins when the plants are only 3 weeks old and continues till the plants die off in autumn or early winter.
  • Spread is by seed. The burr readily attaches to animals, sheep fleece, vehicle tyres and shoes.

Caltrop, photo: Molly Elizabeth Bagley 2002 Caltrop stems and flowers, photo: Jeff Abbas 2001 The spiny burrs of caltrop, photo: CDFA 2001
Image top: Caltrop flower, © Jeff Abbas 2001
Images above left to right: Caltrop, © Molly Elizabeth Bagley 2002; Caltrop stems and flowers, © Jeff Abbas 2001;
The spiny burrs of caltrop seeds, © CDFA 2001

Impacts of caltrop

  • The spiny burr of caltrop causes problems by damaging the feet and mouths of animals, and when the burr becomes entangled in wool. The burrs can also be a nuisance to people such as on playing fields.

Where does caltrop occur?

  • Caltrop is a native of the Mediterranean, Asia, Africa and subtropical Australia. On mainland Australia, caltrop is a problem weed in all states.
  • Caltrop has not naturalised in Tasmania.

What you need to do

  • If you locate caltrop anywhere in Tasmania, or if you find a plant that you think could be caltrop, immediately contact Biosecurity Tasmania on 03 6165 3777 to report this weed.

See also
Caltrop Statutory Weed Management Plan
Weed Links and Resources

Other useful links
Pest Genie

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