10-07-2025
Property owners warned as 'one of world's worst weeds' found in Aussie city for first time
The alarm has been sounded by authorities in the Top End after "one of the world's worst weeds" was discovered in the region for the very first recorded time, with environmental officers urging residents to look out for the aquatic invader and report it. And concerningly, the invasive weed was unwittingly being offered on social media by a local resident.
The weed management branch within the NT Department of Lands, Planning and Environment received a report of a suspicious plant being offered online last week. It led officers to attend a residential property in Darwin's northern suburbs.
There, they took samples of the plant from a contained garden pond which was later confirmed to be Amazon frogbit, an invasive weed capable of choking waterways, prompting a public warning to residents this week.
"The property owner was unaware they had Amazon frogbit and we are thankful a member of the public familiar with such weeds brought this to our attention," a department spokesperson told Yahoo News.
Originally from the freshwaters of Central and South America, Amazon frogbit (Limnobium laevigatum) is a fast-growing, floating aquatic plant that can take over rivers, ponds and lakes, and could pose a risk to Darwin's drinking water, the department said.
Related: Council's warning as popular backyard plant sprouts up in 'hectic' location
Authorities said the weed has been "discovered in the Northern Territory for the very first time" but where it ultimately came from remains unclear.
"The owner informed us that he did not know where the frogbit had come from and stated that it had appeared in the pond around three months ago during the 2025 wet season," the spokesperson told Yahoo.
While the weed is considered a pest on some local government areas in Queensland, it is not actually prohibited in the state and can even be purchased. However south of the border it's a different story. In NSW it is illegal to buy, sell, trade or move it into the state, with on-the-spot fines as high as $2,000 for anyone caught doing so.
"Interstate, it has spread as a result of illegal dumping of fishtanks, aquariums and water features into waterways," the NT Department of Environment warned.
Weed officers in the Territory are now calling on the community to check their ponds for Amazon frogbit, which has smooth round leaves with a spongy underside, and occasional small white flowers. If detected, residents are urged not to dispose of it themselves but rather contact the Territory's Weed Management Branch.
Incidents of accidental or unknowing trade or growing of weeds will not lead to legal action, it added
"The last thing we want is for anyone to remove or dispose of it as this would be the worst possible action to take," the department spokesperson told Yahoo.
🪳Aussies urged to know telltale sign as 'devastating' pest threatens every state
🌴 Homeowners warned over hidden danger of common but 'invasive' palms
🌵 Biosecurity threat 'hiding in plain sight' prompts reminder to Aussies
The leaves of the fast growing plant float on the surface of the water, forming thick mats across freshwater systems. In doing so, the plant can obstruct sunlight and water, and severely impact native aquatic life and block waterways, stormwater drains and irrigation channels.
It is strictly prohibited in NSW, South Australia, Western Australia, the ACT, NT and Tasmania. Despite its lesser status in Queensland, the state government advises all residents have a "general biosecurity obligation" to take reasonable and practical steps to minimise its risks.
The Invasive Species Council of Australia has previously called on authorities around the country to ban weeds like frogbit, as well as English Ivy and gazanias.
