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Farmers, environmental groups and researchers are calling for national regulation to ban the sale of the “highly invasive” weed gazania, a bright but destructive garden plant now threatening Australian farmland including regions in Hawkesbury from Berambing to the Richmond Lowlands strangling grass feed for horses and cattle.
Once introduced from South Africa in the mid-20th century as a hardy, low-maintenance garden flower, gazanias have since spread well beyond backyards overrunning roadsides, coastal dunes, native grasslands, and even cropping paddocks. These plants are in the same family as Cape weed which we often see in the Hawkesbury, I recently saw some on the roadside of Ham Common opposite the RAFF base.
Farmers across South Australia, Victoria and Western Australia have reported severe infestations, with some grain paddocks rendered completely unviable. Weeds and invasive species like gazania are estimated to cost Australian agriculture more than $5 billion each year.
Each gazania flower head can release around 60 windborne seeds, capable of travelling up to 30 kilometres, allowing the weed to colonise new areas rapidly. In some areas in South Australia paddocks are wall-to-wall with gazanias, leaving farmers unable to grow crops at all.
Dr Ali Bajwa, who leads a weed science research group at La Trobe University, said the plant’s resilience made management extremely difficult.
“Gazanias can choke native vegetation and outcompete crops for nutrients, moisture and light,” Dr Bajwa said. “They are inherently tolerant to many herbicides, and that’s why we can’t really control them.”
Dr Bajwa’s team, supported by the Grains Research and Development Corporation, is conducting field trials to test new chemical control options for the weed.
Calls for a National Ban
South Australia has already banned the sale of gazanias, but they remain legal to sell in most other states, including New South Wales and you can purchase the flowering plant and or seeds from Bunnings.
The Invasive Species Council’s engagement director, Imogen Ebsworth, said it was “bonkers” that nurseries could still sell such a destructive species.
“We’ve got over 30,000 introduced plant species in Australia, and most have never been assessed for their weed risk,” Ms Ebsworth said. “People shouldn’t need a botany degree to understand what they’re buying.”
She warned that gazania could easily become the next lantana or blackberry both once- sold ornamentals that now dominate millions of hectares of land.
Residents are encouraged to report sightings of gazania escapes from gardens or road verges to NSW DPI’s Weed Wise https://weeds.dpi.nsw.gov.au/database for identification and control advice.
