CALTROP DESCRIPTION
Caltrop (Tribulus terrestris) is a summer-growing weed found widely throughout Western Australia. It is most common in areas of frequent spring and after summer rain.
Under the Local Government Act 1995 it is a prescribed pest plant in a number of shires in the Perth metropolitan area, the southwest and the wheatbelt.
However it is not a declared plant, and there is no requirement to report it to the Department of Agriculture and Food, Western Australia.
Caltrop has seeds that remain dormant in the soil for probably four to five years. They germinate after summer rain. Plants grow rapidly, flowering and forming new burrs within three to five weeks.
The trailing stems of caltrop are long and wiry. They are covered with fine hairs. The stems lie prostrate on the ground, radiating from a central taproot. The leaves consist of several leaflets arranged opposite each other on the stems. The leaves are fern-like and greyish-green. Caltrop is often confused with doublegee; however, the latter has a green leaf similar to English spinach.
The flowers are small, less than 1cm in diameter, and yellow with five petals. Wedge-shaped burrs are formed in clusters of five, each with four or more long sharp spines.
Under cropping situations the weed is of little agricultural importance as it is a summer-growing plant, which does not affect winter crops. Sheep readily eat it, but there have been a number of confirmed cases of caltrop poisoning in sheep and goats. Caltrop is a nuisance around farm buildings, townsites, railway yards, roadsides, car parks, cycle paths and other recreation areas because of the sharp spiny burrs.
A heavy infestation after summer rain can produce an abundance of spiny burrs, which make it very uncomfortable for people and animals alike.
SIMILAR SPECIES
May be confused with Bindii or Cat's Ear.
SCENARIOS AND SOLUTIONS:
- In garden beds: spot spray Apparent Glyphosate or Gryphon Glyphosate 450 Herbicide.
- In lawns: use Apparent Amine 625.
Reference for image and article: https://www.agric.wa.gov.au/pest-plants/caltrop-what-you-should-know