I laid out these tyres to be stepping stones as well as a boundary between garden sections. The oxalis has pretty much ignored any sense of boundary, or for that matter the unlevel ground around them. You can see though several areas I’d handled the oxalis differently. Behind is the lime tree, with woodchip mulch over weedmat (almost no oxalis), barley mulch over weedmat (close around the lime tree, some oxalis), woodchip mulch where I had cardboard down last year (zero oxalis). Below the tyres is an area I did nothing to. Above the tyres is an area I windowed during summer to kill couch (can’t tell the difference in oxalis growth between that and the area I did nothing to). Then there’s the tyres themselves – the left and centre ones were filled with cheap potting mix. So cheap that the plants I put in them never bothered growing and even the oxalis has taken a bit of a beating. The tyre to the right has no potting mix, it’s just sitting on top of the garden sand which is apparently significantly more fertile than the potting mix. And that’s saying something, given that it’s untreated Bassendean sands. The top right corner is the retention trench, which almost two years ago had all the sand dug out and sifted back in to remove oxalis corms. You can’t now tell.