Nasty thing to have on a nature strip. Here is what the burr looks like. https://vicflora.rbg.vic.gov.au/flora/taxon/dae3606b-41a4-477f-b833-17c85687c48d#&gid=1&pid=1
Must be a tough little plant to grow there with the conditions we have had lately as it is near a road on the nature strip and does not get looked after. Has a cute flower though. It will definitely be left alone. Thanks for your help and advice.