Weed warning for unsuspecting growers

Mature Mexican Feathergrass plants
Mature Mexican Feathergrass plants

Members of the public are being urged to report three weeds which have the potential to devastate agriculture and native ecosystems in South Australia.

These detections follow the release of a Centre for Invasive Species Solutions report into the annual costs of weeds in Australia, which totals almost $5 billion across Australia.

The recently detected weeds are not yet established in South Australia, but they pose a serious threat and are required by law to be reported.

There have recently been detections of:

  • Serrated tussock (Nassella trichotoma) – found in a Naracoorte garden and considered Australia’s worst pasture weed, and also dominates native grasslands. It costs $50 million annually in lost production and control costs and is also a fire hazard.
  • Mexican feathergrass (Nassella tenuissima) – found in gardens in Aldinga, Clarendon, Hayborough and Port Elliott, has similar impacts to serrated tussock.
  • Horsetails (Equisetum spp.) – found in a number of gardens in Adelaide, toxic to livestock and highly invasive.

Biosecurity SA General Manager - Strategy, Policy & Invasive Species Unit Dr John Virtue said the common thread between the three weeds is that they were grown in people’s backyards.

“These people thought they were growing an ornamental or native plant – they had no idea they were growing a highly invasive weed,” he said.

Horsetail plant growing in a metro Adelaide

Horsetail plant growing in a metro Adelaide

“Our concern is to stop these weeds from being grown and eventually becoming established in South Australia, but we need the cooperation of everyone, particularly the gardening community.

“There is a history of people inadvertently introducing plant species into their gardens which are interesting or attractive, without realising the impact they could have if they spread into the environment.

“We are very grateful to those people who had the foresight to check what they were growing before they planted or shared their plants.

“Both serrated tussock and Mexican feathergrass look very similar to some of our native grasses, so if you are growing these sorts of plants in your backyard and don’t know exactly

what they are, take the time to make sure you get them identified.

“Horsetails had been grown as pot plants, but if even a small amount of this was to establish in our natural wetlands and watercourses it would be extremely difficult to control.”

All three of these plants are illegal to grow, distribute or sell in South Australia. If you think you may have found one of these species, contact your local Natural Resources office or Biosecurity SA on (08) 8303 9620, who can help identify, remove and dispose of them.

Serrated Tussock plant

Serrated Tussock plant