2 more votes for Japanese anemone and crocosmia here. Slightly concerned re Lily of the Valley comments, have recently planted 4 clumps. When I rented out my house a few years back, the tenants planted Macleaya, I managed to get rid of it - what horrid bright orange roots it had. Oh and I still get the odd acanthus leaf poking through, but that's removed on sight. One advantage of having very dry light soil is that digging these thugs out is relatively easy, I would imagine it's a nightmare on anything heavier.