The Sticky Secret of Acaena novae-zelandiae— Why It’s More Than Just a Nuisance
© Mykal Hoare 2025
Some plants are simply irritating. Not irritating in terms of skin rashes or allergic reactions, but physically annoying. Their seeds get stuck to your socks and shoes, maybe in your leg hairs or your pup’s fur. You track them everywhere you go! You spend what feels like forever picking them off. This happened to me numerous times while camping along the Victorian coastline over the summer holidays. When I stopped to look at the cause of my annoyance, I came to find Acaena novae-zelandiae, commonly known as Red bidibid, bidgee-widgee, buzzy and piri-piri bur. It is actually a fascinating plant that graces landscapes across the southeastern states of Australia. Other than being a slight nuisance, it’s actually a very interesting species. Its unique appearance and wide range of uses have made it a subject of interest. Indigenous populations use Acaena novae-zelandiae in traditional medicines, applied both topically and taken orally.
A Snapshot of Acaena novae-zelandiae
Photographed along the rugged beauty of the Victorian coastline, Acaena novae-zelandiae is a small, tough, herbaceous perennial ground cover or prostrate plant that thrives in various habitats. It is endemic to Australia, New Zealand, and New Guinea and has now naturalised in California and the British Isles.
Novae-zelandiae is a very distinctive-looking plant. Its dark green leaves are oblong and toothed, taking an imparipinnate form. Its red pom-pom-like flowers sit proudly above the rest of the plant, slowly fading to brown and forming spiky burr-like seed heads, waiting for an animal or an unaware camper (me) to brush past to disperse the seeds far and wide. While it may seem like just another plant, its history and cultural uses tell a story of importance and utility.
© Mykal Hoare 2025
Traditional Medicinal Uses
Australian Indigenous cultures have long recognised the medicinal properties of Acaena novae-zelandiae. The young leaves of this plant were traditionally used to prepare a tonic believed to promote overall health. This tonic was particularly valued for its ability to address issues related to the kidneys, bladder, and stomach.
The plant's leaves could be crushed into a paste or made into a wash that was applied topically to wounds. This natural antiseptic treatment helped prevent infections and promoted healing. Acaena novae-zelandiae was highly important to the lives of Indigenous communities throughout its local range. (This article is for informational purposes and not medical advice.)
The Burs and Their Role in Seed Dispersal
One of the most notable features of Acaena novae-zelandiae is its burrs. These small, spiky structures play a crucial role in the plant's reproduction by aiding seed dispersal. However, their method of dispersal can be somewhat troublesome. The burrs latch onto anything that brushes against them—shoes, clothing, animal fur, and more. They travel great distances before eventually falling off, ensuring the plant's seeds are spread far and wide.
While this mechanism is a brilliant evolutionary strategy for the plant, it can be an annoyance for those who find themselves repeatedly picking the burrs off their belongings. Nonetheless, this characteristic contributes to the plant's resilience and widespread presence across various regions.
© Mykal Hoare 2025
Garden Use
Personally, this is not a plant I’m looking to implement into garden landscapes due to its weedy, invasive nature. Not to mention, pulling burs from socks has to be one of my least favourite pastimes.
That being said, there are some use cases for Acaena novae-zelandiae in Australian home gardens. They are amazing at stabilising loose soils, slopes and banks, aiding erosion control. They are also very tough, resilient plants, being both frost and drought-tolerant.
If you have bare spaces in the garden, A. novae-zelandiae’s vigorous growth will fill them quickly and start attracting Aussie wildlife, providing food for Australian native birds.
I’d recommend placing Acaena novae-zelandiae far away from paths and parts of the garden you frequent, as well as keeping it far away from lawns, as they will happily replace your lawn as a ground cover since they don’t mind being hit by the mower.
Presence in the United kingdom.
There are two theories as to how Acaena novae-zelandiae is thought to have made its way to the other side of the globe and naturalised in the United Kingdom. The more interesting, is by hitchhiking on wool products being sent back to the UK during Australia’s wool boom between 1870 and 1901. A. novae-zelandiae was first recorded in the UK wild in 1901.
The second and more obvious theory is that the species was introduced in the ornamental plant trade and escaped into the wild through its ease of seed dispersal and dumped plant materials.
Acaena novae-zelandiae is not currently on an Uk governments limited List of invasive plant species but it likely should be. It poses threat to the UKs native plant species as it forms dense cover over the landscape out competing British native species making it detrimental to native ecosystems.
The species seems to be absent elsewhere in Europe with the exception of Denmark where it is classified as established, non-invasive, rare alien. But has been declared a noxious weed in the US states of Oregon, California and Hawaii.
Read the detailed report by GB NNSS
Acaena novae-zelandiae is more than just a plant that grows along the coastline; it is evidence to the lond standing symbiotic relationship between nature and humans. Its medicinal properties make it a plant worth appreciating and studying. Above all Acaena novae-zelandiae offers a glimpse into the rich cultural and botanical heritage of Australia.