Asclepias curassavica L.
annual milkweed, bastard ipecac, blood flower, blood-flower, bloodflower, bloodflower milkweed, butterfly weed, false ipecac, Indian root, Mexican milkweed, milkweed, red head cottonbush, redhead, red-head cotton bush, redhead cotton bush, red-head cotton-bush, red-head cottonbush, redhead cottonbush, scarlet milkweed, silkweed, swallow-wort, tropical milkweed
Asclepiadaceae (the ACT, Victoria, Tasmania, South Australia, Western Australia and the Northern Territory)Apocynaceae (Queensland and New South Wales)
Widely naturalised in Australia, but most common and widespread in the eastern parts of the country (i.e. in eastern Queensland and the coastal districts of northern New South Wales). Also naturalised in southern and north-western Western Australia, in the north-western parts of the Northern Territory, in southern Victoria, in the coastal districts of central New South Wales and in some parts of eastern and southern South Australia.
This species is regarded as an environmental weed in Queensland and Western Australia. It is a common weed of pastures, disturbed sites, waste areas and roadsides and is also found in natural areas (i.e. wetlands, waterways, open woodlands and grasslands).
Red-head cotton bush (Asclepias curassavica) was recently ranked among the top 200 most invasive plants in south-eastern Queensland, and it is mainly a concern in riparian areas and wetlands in this region. In Western Australia it has been found growing in reasonably intact bushland as well as disturbed urban bushland, from Carnarvon to Mandurah.