â€œAlthough native plants and animals had supported the needs of Australian Aborigines for food and clothing over thousands of years, the first European settlers found the Australian flora and fauna particularly unsuited for their purposes.
There were no native plants related to the cereals such as wheat, oats, barley and rice; no obviously edible fruit such as plums, apples and citrus; no fibre plants such as flux, jute or cotton; no traditionally edible animals such as cows sheep or pigs; and no animal product such as milk wool or eggs.
It was felt it was necessary to import all of these plants and animals from Europe and establish them in the new colony. Not only plant species of such direct use were imported, but also a wide range of ornamentals, hedge plants etc. In 1803, only 15 years after the arrival of the first fleet, governor King listed 292 introduced food and ornamental plants then growing in the colony and requested that a further 82 be sent from England. Of those introduced, it appears that at least nine, including furze, english broom and sweet briar, subsequently became important noxious weeds. There seemed to be little thought that indiscriminate introduction could lead to serious problems in the new environment.â€
W.T. Parson & E.G.Cuthbertson
Noxious Weeds of Australia, 2001