Cobbler’s pegs (Bidens pilosa)
Cobbler’s pegs (Bidens pilosa )
Family: Asteraceae (daisies)
An erect annual or perennial herb with branching habit to about 1m high. Leaves are deeply divided into three toothed lobes, with the terminal lobe larger than the other two. Individual flowers are yellow but are tiny and held in dense terminal clusters in a widely branching flowering head. Each flower cluster has four or five short, broad, white "petals" but these do not persist for very long. The seeds are black, about 1cm long, with 2 or 3 barbed awns at the tip. These adhere to clothing.
Preferred habitat and impacts:
Generally found growing in full sun or partial shade on grazing land, roadsides or waste ground, but it also invades remnant grassy vegetation in farming areas. It will tolerate dry infertile soils and often is most prolific on warm north-facing rocky slopes. Burrs are a nuisance on sheep and other fleece-producing livestock, and to people.
Burrs attach to livestock, clothing, and are spread in mud and soil. They float on water.
No other plant looks very similar, except for the native Indian weed (Sigesbeckia orientalis ) another member of the daisy family which has yellow flowers. Its leaves are arrowhead shaped, not three lobed, and although its seeds do stick to clothing, and skin, they do so because they are sticky, not with hooked hairs.
Another weed in the daisy family, fleabane (Conyza albida ) is also often referred to as cobbler’s pegs, because of the shape of the flower buds.
Chip or hand pull prior to the burrs forming, or spot spray. Take care to avoid walking through seeding plants and spreading the seed. If removing seeding plants, bag them for burning or deep burial, to avoid spreading the seed.