Hi there, I live on the Gold Coast in Queensland and found an unknown plant growing in the garden (see attached picture). It looks similar to Acanthus Mollis but has some serious looking thorns on its stems. Any ideas as to its common/botanical name?
Acanthus literally means thorns and there is speculation that it is responsible for the Crown of Thorns in Christendom. It could be you are accustomed to cultivars that don't have thorns but I think you are spot on with your genus guess. It is invasive in some areas and spreads by underground rhizomes.