This stuff grows anywhere, tolerates poor and dry soil, strikes from small pieces. Small yellow flowers. The blue tongue lizards like it.
I was a bit concerned about weed potential but it seems to spread, not jump and is easy to pull out. To kill completely, just sheet-cover or out-compete. Alyssum can beat it.
August 2014: I am going to try it on the front verge to replace the grass and weeds between the fenceline and the path. Easy striking means lots of free plants. The aim is something that needs no mowing and no watering.
December 2016: Sedum is still growning in places on the verge but it is not as hardy as expected.