Prostrate annual, herb, plants villous; leaflet pairs 4-7; cocci with distinct divergent, median spines 3-8 mm long. Fl. yellow, Jan to Dec. Often on sandy soils. Waste places.
General Biology. Growth form. Herb. Life form. Annual. Reproduction. Seed 'nutlets'. Dispersal. Dispersal of the burrs via tyres, water, machinery, soil movement and adhesion to animals, clothing, footwear.. Time of first flowering. Within three weeks of germination. Time of first fruiting. Within five to six weeks. Seedbank persistence. Can remain domant up to 5 years..
Notes. Caltrop produces sharp, spiny burrs throughout summer and autumn. Up to 1000 fruits can be produced on each plant, with a total of up to 20,000 seeds. Plants grow rapidly, flowering and forming new burrs within three to five weeks..
Additional information. Origin. Native to the Mediterranean, Africa, Asia and subtropical parts of Australia.. History of use/introduction. Thought to have been introduced to Southern Australia through contaminated seeds from Europe.. Similar exotic species. Tribulus cistoides. Similar native species. Tribulus occidentalis.
Suggested method of management and control. Preventing the spread of Caltrop is the best control measure. Prevent spread through cleaning of equipment, clothing, vehicles that have been used in infested areas. Hand removal can be effective for small infestations, care must be given to removing the deep tap root and the seeds should be burnt. Herbicide use can also be effective, spraying needs to be done before seeds set and repeated for each germination of seedlings. Pasture management or renovation to provide competition is often the key to caltrop control in pasture. Read the manufacturers' labels and material safety data sheets before using herbicides. For further information consult the Australian Pesticides and Veterinary Medicines Authority to determine the status of permits for your situation or state.
Legend: Y = Yes, regularly, O = Occasionally, U = Uncertain, referred by others but not confirmed.