WIDESPREAD PEST: Cobbler’s pegs (Bidens pilosa) are native to Central and South America but are invaders here.
WIDESPREAD PEST: Cobbler’s pegs (Bidens pilosa) are native to Central and South America but are invaders here. Contributed

Cobbler’s pegs hard as nails

COBBLER'S pegs (Bidens pilosa) are native to Central and South America, but they are known widely as invasive weeds in other tropical and sub-tropical regions, including Eurasia, Africa, Australia, and the Pacific Islands.

Cobbler's pegs plant gets is common name from the barbed seeds which resemble shoe nails which were used in the past by cobblers to make and repair shoes.


This plant is considered a weed in crops, sunny disturbed areas in urban and rural areas, or as a common garden weed.

However, in some parts of the world it is a source of food or medicine. For example, in sub-Saharan Africa, the tender shoots and young leaves are used fresh or dried as a leaf vegetable, particularly in times of scarcity.

I feed it often to my aviary birds and guinea pigs.

It spreads mainly by the seeds which use two barbed awns (stiff bristles) to stick to clothing, fur of animals, on vehicles or machinery, or even on the hairs on human legs.

It also produces massive amount of seed, which produce large populations of monoculture plants.

These successful reproductive strategies have helped the cobbler's peg plant become a noxious weed in temperate and tropical regions of the world.


Bidens pilosa is an annual plant, growing up to 1.8m tall. The plant dies in dry periods or in winter frosts.

The fruits are dark brown, slightly curved, stiff, rough black rods, tetragonal in cross section, about 1cm long, with typically two to three stiff, heavily barbed awns at ends.

The plants are a characteristic dark green colour and often do not develop flower-heads until at least one metre tall.


Most herbicide products will kill cobbler's pegs (Bidens pilosa) easily but its reproduction and survival strategy of its mass seed production makes several follow up weed control applications necessary.

Individual plants usually are easily hand pulled in most soil situation but it has a strong tap roots and it also produces roots along the stem where it comes in contact with the soil which can make hand pulling more difficult to do.

Cultivation easily removes most plants in a large infestation but some plants will re-root if not totally removed.

Landcare contacts

Ian Read can be contacted 0741599365, or email ian.read7@bigpond.com.au for free weed identification and native plants advice, and for landscaping and weed control.

Phone Landcare president Michael Johnson on 0422297062 for weed project details and monthly meeting times, or email bundylandcare@gmail.com

The Bundaberg Landcare Nursery at the Salvation Army Tom Quinn Centre, Doctor May's Rd, is open on Wednesdays, Thursdays and Fridays, 10am-4pm.

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