A year ago, this black wattle was just a metre high and virtually invisible among the native plants. It grows fast and reproduces freely and would, if left unchecked, replace all of the indigenous flora.

It is not generally known that there are more illegal Australians in the Western Cape than law-breaking South Africans. My wife and I are two of the interlopers. We try and justify our presence by removing thousands of Australians every year. When we arrived in this elevated valley above Wellington, we were greeted by a grey-green landscape of mostly protean renosterveld, patched here and there with the seaweed-green of tall bushes.
When we walked though the native flora, we encountered hakea sericea, originally imported to tame the Western Cape sand dunes, acacia saligna and acacia mearnsii, known as Port Jackson wattle and black wattle, respectively, and several different eucapyptus, broadly known as gum trees, which unwelcome invaders over much of the temperate zones of the whole planet.
The populations weren’t yet critical, but we found that the carpeted hillsides of protea bushes were peppered with baby wattle, hakea and gum trees.
It became clear that our fellow Australians would soon obliterate the slow-growing local flora. So we confess that we have become involved in planticide.
And now we even support the Springboks against the Wallabies.