This is a form of lantana. As Bunty says there is a lantana that is termed as noxious in both Australia and South Africa. The one we used to get in Amazimtoti grew to huge proportions and was thorny. This one seems to be a lot smaller and I didn't see any thorns. It looks very similar to the one I photographed outside the casino at Niagara Falls, in a flower bed. See my https://ralpapajan.blogspot.com (No "s"! Sorry about confusion that may result. Long story.)
