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Farmers across the Hawkesbury are facing a growing challenge from fleabane, a tough and fast-spreading weed that has developed resistance to glyphosate, one of the most commonly used herbicides in Australian agriculture.
The invasive plant, originally from the Americas, has quickly adapted to local conditions and is now thriving across paddocks, roadsides and river flats in the Hawkesbury region. Agricultural experts warn that fleabane is costing producers time and money to control, while also competing with crops and pasture for valuable moisture and nutrients.
Fleabane has become one of the most difficult weeds to manage on-farm,” said Phil Burkitt, a horticulturalist who lives and works in Hawkesbury. and western Sydney regions. “ resistance to glyphosate means farmers need to combine multiple control strategies — not just rely on spraying.”
Fleabane belongs to the Conyza genus, with six species naturalised in NSW. The most common, Flaxleaf fleabane. Conyza bonariensis, grows up to a metre tall, is grey-green and very hairy, with toothed leaves and whitish flowers that appear for most of the year. Other species found in the district include Tall fleabane. Conyza sumatrensis, which can reach two metres, and Canadian fleabane. Conyza canadensis, a lighter yellow-green plant with small brownish flowers.
Local Hawkesbury farmers say the weed has been spreading rapidly across properties and along fence lines in recent seasons.
Each fleabane plant can produce more than 100,000 tiny seeds, which are easily carried by wind or attached to animals, machinery and vehicles. Once established, the plant’s deep taproot makes it difficult to remove, and its seedbank ensures it can return year after year if left unchecked.
Local regeneration groups are also monitoring its spread in bushland and river corridors.
“It’s not just a problem for farmers — it’s turning up in native regrowth areas too,” said Burkitt. “We’re seeing it compete with native species along the river and in revegetation sites, so community control efforts are really important.”
Farmer and growers are urging an integrated weed management approach, combining targeted herbicides, cultivation, competitive cropping, and maintaining ground cover to prevent fleabane from setting seed.
For futher infomation the https://www.dpi.nsw.gov.au/dpi/biosecurity/invasive-plants-and-animals/weeds provides information on weed control and biosecurity, with resources for identifying, reporting, and managing weeds.
