Siam weed can kill your cattle


One of the world’s most invasive weeds continues to make its way across the Top End and we need your help to manage infestations.

Siam weed was first confirmed in the Northern Territory in July 2019, and aerial surveys in 2021 revealed the weed had spread 100km from the initial infestation site to cover more than 10 properties.

The Department of Environment, Parks and Water Security continues to work closely with landholders to manage the spread, and is urging the public to be on the lookout and report any sightings to us.

The parachute seeds are dispersed by wind and water and contain fine barbs that readily stick to clothing and fur. Siam weed is easily spread long-distances through contamination of vehicles, equipment and produce.

Siam weed grows and spreads best where annual rainfall is 600mm or more and kills around 3,000 cattle annually in the Philippines.

It blossoms in June-July with pinkish-white flowers and is identifiable by its large stem and leaves both of which resemble a ‘pitch-forking’ pattern.

Detection of new Siam weed infestations across the Top End is fundamental to the success of the current management response.

You can find out more, including how to identify and report the weed, on the Northern Territory Government website.

Quotes by Department of Environment, Parks and Water Security, Siam weed Project Officer, Tom Price

“Siam weed is highly invasive and is toxic to livestock. It can also cause skin complaints and asthma in allergy-prone people.

“We need help from the public to identify the weed on their property and report it to help manage the spread in the Northern Territory.

“If you suspect it, report it. It is critical any new infestations are reported to determine Siam weed’s distribution across the landscape.

“Contact the Weed Management Branch immediately for assistance on 08 8999 4567.”

Man inspecting siam weed

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