Common agricultural and backyard weeds

Members of the community regularly come into the Project Platypus Office with queries regarding common agricultural weeds encountered in the upper catchment.

Caltrop, Bindii (Tribulus terrestris)


Caltrop is a flat, sprawling, summer-growing, annual herb. It has become a weed of cultivated crops, orchards, over-grazed pastures, stock yards, roadsides and neglected areas, particularly in districts with high summer temperatures and dry sandy soils where there is little competition.

In Victoria, caltrop is most frequently found in the north of the state, the Mallee, northern Wimmera and northern region.

Capeweed (Arctotheca calendula)

Capeweed Native to South Africa. Naturalised across the southern half of Australia.

Widespread and common weed of pastures, lawns, cultivation and waste areas across Victoria. Typically a plant of fresh-water habitats but may occur on the fringes of saline swamps and flats during wetter periods.

Scotch Thistle (Onopordum acanthium)


Probably introduced as an ornamental. A weed of pastures, crops, disturbed sites, waste areas, gardens and roadsides. It is mainly found in temperate regions, but occasionally also grows in semi-arid and sub-tropical environments. Listed as a noxious weed of Victoria in 1856.

Onion Grass (Romulea rosea)


Native to southern Africa. Common onion grass (Romulea rosea) was deliberately introduced and cultivated as a garden plant. A very common weed of lawns, footpaths, parks, roadsides, gardens, pastures, crops, disturbed sites, waste areas, grasslands, open woodlands and wetlands in temperate regions.

Cork Screw (Erodium botrys)


Annual. Widespread, common, occurs on roadsides, pastures, grasslands, on fertile soil. Regarded as an environmental weed in Vic. Major issue for sheep graziers as corkscrew-like seed contaminates wool and gets into the ears and eyes of livestock causing damage.

Marshmallow (Malva parviflora)


An annual or perennial herb that is native to Northern Africa, Europe and Asia and is widely naturalised elsewhere. Plants grow quickly from seeds, develop flowers within a few weeks and flowers set seed that are mature within 21 days.

Stinging Nettles (Urtica dioica)


Nettles are tough, tenacious, colonising plants that usually occur in cultivated or disturbed soil. They’re a good indication that the soil is quite high in nutrients, especially phosphorus. Widely naturalised, particularly in southern and eastern Australia.

Sorrel (Acetosella vulgaris)


Native to western and central Europe. This species is widely naturalised in Victoria. A long-lived (perennial) herbaceous plant with creeping underground stems (i.e. rhizomes) and upright branched flowering stems 10-60 cm tall. Sorrel is regarded as an important environmental weed in crops and pastures and it invades a wide variety of natural habitats.

Sour Sob (Oxalis pes-caprae)


Indigenous to South Africa. Sour Sob has a reputation for being difficult to eliminate once it has spread over an area of land. It propagates largely through its underground bulbs and this is one reason why it is so difficult to eradicate, as pulling up the stems leaves the bulbs behind. Soil in which the plant has grown is generally contaminated with many small bulbs.

Plantain (Plantago sp)


Widely naturalised. Common weed of disturbed sites including roadsides. persistent taproot. Has longevity of 1-3 years.

Pig Weed (Portulaca oleracea)


Pig weed has an extensive distribution, assumed to be mostly anthropogenic.  It is an annual succulent in the family Portulacaceae, which may reach 40 cm (16 in) in height.

Hog/Wire weed (Polygonum arenastrum)


Native almost throughout Europe. An occasional weed of bare open ground (including cracks in pavements, roadsides, fallow paddocks etc.) mostly on compacted or heavier soils.