War on weeds

PUBLISHED : Friday, 11 March, 2005, 12:00am
UPDATED : Friday, 11 March, 2005, 12:00am

Hatred is not an emotion you often associate with flowers. But it took me less than an hour to come to loathe an innocuous looking plant called mother-of-millions.

It was while doing some volunteer wildlife conservation work on an island in the middle of Sydney Harbour that I first encountered the plant. It was everywhere - smothering the bush, growing from rock niches and scattered along the top of sandstone cliffs. Our small group of volunteers was told to show it no mercy.

Mother-of-millions is one of thousands of exotic plants which have gone wild after being introduced to Australian gardens. They have long been regarded as a serious problem, crowding out native species of plants and trees, and skewing the balance of nature.

This week, the WWF warned that the ecological threat from invasive plants is so serious that 10 species should be banned outright. A report written for the group by government scientists estimated that exotic weeds cost Australia at least A$4 billion ($24.7 billion) a year in lost agricultural output and eradication efforts. 'Many escaped garden plants contribute substantially to this cost,' the report said. Among the most invasive of the garden plants were such harmless sounding species as Japanese honeysuckle, fountain grass, periwinkle and the dreaded mother-of-millions.

Kikuyu grass has gone crazy in South Australia, asparagus fern is out of control in Tasmania and Victoria, and Queenslanders are battling a plant called murraya. The bitou bush, first introduced from South Africa in the 19th century to help stabilise sand dunes, now covers vast areas of Australia's east coast, from Queensland to New South Wales.

The government spends A$80 million a year on the war against weeds, but it also relies on the efforts of thousands of unpaid volunteers. The WWF says that laws to prohibit garden centres from selling some plants are 'an urgent priority'.

There are no less than 27,000 introduced plant species in Australia, the vast majority of them used in gardens. Environmentalists say new plant species being imported should be carefully screened and only those posing a low risk to farming and ecosystems should be allowed in. But any such move will be fiercely resisted by the multimillion-dollar garden-centre sector.

In any case, it is hard not to conclude that the fight against invasive species is already a lost cause. It is as daunting a challenge as trying to remove the rabbits, foxes, cats, camels and donkeys which have caused such damage to Australia's unique environment. The war on weeds is likely to be never ending.