Acaena novae-zelandiae is a shrub (stem succulent) that is not native to California.
There is a high risk of this plant becoming invasive in California according to Cal-IPC.
[Cal-IPC] Australia, New Zealand, New Guinea native, Invasive: Acaena novae-zelandiae (biddy-biddy) is a herb/subshrub (stem succulent) (family Rosaceae) with white flowers found in the coastal ranges of California. A pale reddish colored burr is left after the flowers fall. It is native to Australia, New Zealand and New Guinea. It favors dunes, grasslands, and scrub and chaparral habitat. It can spreads via roots and by stem fragments. It disperses by burrs attaching to the fur and feathers of animals and clothing of humans. (link added by Mary Ann Machi)
Calflora:
Information on California plants for education, research and conservation,
with data contributed by
public and private institutions and individuals.
[web application]. 2025.The Calflora Database
[a non-profit organization].Available:
https://www.calflora.org/(Accessed: 03/28/2025).