It’s a Pitch-forking weed!

A pitch-forking weed that can make cattle and country sick is the focus of a new awareness campaign.

Siam weed (Chromolaena odorata) was detected south-west of Darwin for the first time last year and is now flowering, making it more easily identifiable.

The weed's identifying features include pinkish white flowers, opposite leaves and a pitchfork pattern on the leaves.

Anyone who comes across what they think might be siam weed is urged to contact the Department of Environment and Natural Resources (DENR) weed management branch immediately on 08 8999 4567.

Darwin regional weed officer Chris Collins said vital industries such as agriculture and horticulture could be placed under severe threat if siam weed spreads beyond control, as it has done in Queensland.

"Siam weed is dangerous and can make cattle and country sick," Mr Collins said.

"It is regarded as one of the worst weeds in Australia because of its invasiveness, potential for spread and environmental and economic impacts.

"Siam weed smothers plants and poisons animals. It can also cause skin complaints and asthma in allergy-prone people.

"If left untreated it has the potential to spread across northern Australia and down the eastern and western coastline.

"Prevention and early intervention are the most cost-effective methods of weed control and we are working hard to ensure this outbreak is addressed strategically and rapidly.

That's why we have launched this awareness campaign and are urging the public to be on the lookout for Siam weed and report any possible sightings to us by calling 08 8999 4567."

Native to the Americas, Siam weed is now a serious threat to plants, animals, people and the economies of Africa and tropical parts of Asia.

It remains unclear how the weed managed to find its way into the Top End and last year's detection south-west of Darwin remains the only recorded infestation of Siam weed in the Northern Territory.

Anyone who thinks they have Siam weed on their property, or thinks they have seen it, is urged to contact the DENR weed management branch on 08 8999 4567. Go to for more information about Siam weed.

Last updated: 11 June 2020

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