Not sure that's what they mean by 'foundation plants'. I thought it meant the shrubs etc planted around the foundations of the house ie around the base of the walls.

O really. They always looked a bit green and kinda nondescript...you know, space fillers, so I might be a bit off centre here. I kinda thought they meant foundation, meaning those often evergreen garden 'bones' such as, I dunno, hydrangea, physocarpus, viburnum, berberis, hypericum escallonia. Not terribly thrilling but to create some sort of living...well, foundation. Have probably wildly offended everyone now...

Have been on a spree buying not very exciting (but ever so useful) stuff myself, mind. Sedums and saxifrage and such.

Yes, floral's explanation is dead-on. Typically, these are broadleaved evergreen shrubs used to 'hide' or camouflage a concrete or masonry block foundation, although the issue has expanded over time to encompass more plant variety as well as often losing the 'hiding' aspect as well.

I've grown a couple of types of Aster lateriflorus over the years in various gardens and would not consider it very 'ground hugging'. In fact it is much more upright (to 3 feet or so) and shrub-like than any other aster I have grown.

Have you considered wood aster, A. divaricatus? This has a very rambling, scrambling, close to the ground habit that you may be looking for. And also moderately drought tolerant once established.

Ah, cheers, GG. Not really ground hugging, just space taking, was what I meant. Literally, I need plants which make a fat clump instead of my usual preference for airy types with a minimal footprint. It was the shrub-like aspect I was really wanting, to fill all those spaces between much taller things, with foliage which starts from the ground...mainly, to attempt to block my idle neighbours weed-infested horrors - although I also wield a vicious strimmer to attempt to keep some sort of separate paths between me and them.