Opuntias are a genus of cacti that includes the infamous Prickly Pear and the Velvety Tree Pear, which is profiled on the facing page. There are no cacti native to Australia, but they grow incredibly well here, especially in drier parts of the country.

Prickly Pear (Opuntia stricta). Only grows to ~1m high. Yellow flowers, yellow prickles and red-purple ripe fruit.
Tiger Pear (Opuntia aurantiaca). This low-growing scrambling Opuntia has long, square-looking stems, barbed spines, yellow flowers and red ripe fruit. It generally grows in wetter areas such as around dams and wetlands. Tiger Pear lacks viable seed and only reproduces asexually.

There are many factors that make Opuntias difficult to control and manage. Firstly, they reproduce and spread across the landscape easily. Their reddish-purple fruits are readily eaten by wildlife and their seeds are dispersed in the scats of bird, feral pigs, deer, foxes and small mammals. All Opuntias also reproduce asexually from a leaf pad or fruit that has landed on the ground. So if a large tree pear falls to the ground, it can sprout from every live leaf pad that touches the ground. The vegetative parts of cacti can also easily get caught and distributed in vehicles, footwear, wildlife, livestock, floodwaters and dumped garden waste.

Bunny Ears (Opuntia microdasys). This Opuntia is of particular concern in SEQ as it can spread quickly and is popular with cacti collectors. Any Bunny Ear plants (in the wild or in cultivation) must be reported immediately to Biosecurity Queensland (phone 13 25 23). A Biosecurity Officer will attend the site and advise on control measures. Bunny Ears lack the obvious spines of other Opuntias, but it is covered in yellow or white hair-like prickles that cause serious skin irritations. The leaf pads often grow in pairs giving the appearance of bunny ears. In the past two years, numerous cultivated backyard Bunny Ears plants have been found throughout SEQ and have been immediately controlled by authorities. Photos thanks to Biosecurity Queensland.

Secondly, there are no naturally occurring insects or animals that control weedy cacti, except for the biocontrol agents that have been deliberately introduced. Thirdly, cacti are popular ornamental garden plants and are collected, propagated and sold in backyard nurseries. Some are even sold online and are posted to buyers as cacti can survive long periods without light or water.
There are 12 species of weedy cacti established in Queensland and they are difficult and expensive to manage. Once naturalised, cacti pose a serious risk to people, wildlife, stock and agriculture.

Velvety Tree Pear (Opuntia tomentosa). The most common Opuntia in SEQ covering thousands of hectares of land across Queensland. Red flowers, grey prickles and red ripe fruit. Its leaf pads are velvety to touch. It can grow to 10m tall.

This article focuses on the four most commonly found Opuntias in SEQ. All are regulated (banned) under the Biosecurity Act 2014. The Indian Fig (Opuntia ficus-indica) is one to watch out for. It is currently unregulated and cultivated for its fruit, however this species can escape into bushland, especially ironbark and Brigalow forests, and may become an invasive weed in the future.
A team at Biosecurity Queensland is tasked with managing the illegal trade of regulated cacti in SEQ. Over the last financial year, they seized over 1600 regulated cacti from 18 different species. If you want to grow cacti, only buy them from registered nurseries. If you are aware of banned cacti being kept or sold, please call your local council or Biosecurity Queensland on 13 25 23. Many of the regulated cacti infestations in Queensland started out as ornamental backyard garden plants.

Deborah Metters
Regional Coordinator
Thanks to Martin Bennett at Lockyer Valley Regional Council and Stacy Harris at Biosecurity Queensland for help with this article.

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