Property owners sound alarm over painful, deadly threat invading Aussie landscape

A recent study found this toxic species to be Queensland's most costly weed since 1960. It's been deemed not containable and continues to spread.

Farmer Ken Stower prods a harrisia cactus.
Harrisia cactus can pierce through tyres and even animal hoofs, inflicting enormous pain. Ken Stower lost a prized bull to the species. Source: ABC

Landowners in the country's north are desperately calling on governments to ramp up efforts in controlling one Australia's most invasive plant species. They say the introduced threat is wreaking havoc across the agriculture sector, even forcing the euthanasia of some livestock.

The harrisia cactus was originally introduced to Queensland as an ornamental plant in the 1800s. But, it's since spread aggressively, particularly across the state's northeast and in northern NSW, where the invasive pest thrives in arid and semi-arid regions.

Its ability to grow in poor soil and reproduce through seeds or broken segments has contributed to its rapid colonisation of rangelands. It invades pastures, reducing grazing land for livestock by forming dense thickets that are difficult to remove.

Its spines can injure animals, while its fruit, though eaten by some native and introduced animals, helps disperse its seeds, further spreading the infestation. The plant disrupts native ecosystems by outcompeting local vegetation and altering habitats.

The harrisia cactus, an invasive plant species in Australia.
Harrisia cactus was first introduced to Queensland in the 1890s as a pot plant. It's since escaped and penetrated much of the state. Source: Queensland Government

Queensland man Ken Stower, who owns a 1,400-hectare property at Captains Mountain, 220 kilometres west of Brisbane, said the species was responsible for the death of his prized $20,000 bull.

ADVERTISEMENT

He said after the animal trod on the cactus, he was left with no choice but to put it down. "We had to euthanise him — it was difficult financially as well as mentally," Stower told the ABC.

"The spines are quite capable of going through a [four-wheel drive] tyre and if they can go through that they will quite easily go through an animal."

Fellow Queenslander Sally McKeering also had animals injured by the plant. McKeering, who works on her cattle property near Alpha, over 400km west of Rockhampton, once fell into the cactus and suffered an excruciating injury.

She required surgery to remove the weed's needles that were deeply imbedded in her hand, having pierced through her gloves, puncturing her wrist.

"I've had a few really good horses that have been pretty much crippled from cactus getting in their coronet band just above their hoof," she said.

The harrisia cactus, an invasive plant species in Australia.
Its razor-sharp needles are known for injuring livestock, and cause excruciating pain. Source: Queensland Government

Efforts to control harrisia cactus include mechanical removal, chemical treatments, and biological control, such as the introduction of a mealybug that specifically targets the weed. But managing harrissia remains a costly and ongoing challenge for landowners and environmental authorities.

ADVERTISEMENT

A 2021 study found it was Queensland's most costly weed since 1960. Sadly it's been deemed not containable.

While mealybugs are working well on some farms, they must be manually transported, which poses a logistical challenge.

The Invasive Species Council has long pleaded with the federal government to "deliver on its promise for a national plan" to address escaped weedy garden plants and introduced threats, which it said costs the Australian agriculture industry over $4 billion to manage per year.

The Council's Campaign Coordinator and bush regenerator Kathleen Herbert told Yahoo News Australia that as it stands, self-regulation within the industry is "just not working" — meaning government intervention is "the only way to solve this problem".

ADVERTISEMENT

Herbert said in particular, hundreds of Australian nurseries — including hardware heavyweight Bunnings — still stock plants and seedlings that have been deemed highly invasive and harmful to our natural environment. They are doing so entirely in accordance with the law, which is something she hopes to change.

Love Australia's weird and wonderful environment? 🐊🦘😳 Get our new newsletter showcasing the week’s best stories.