Yes, neither of them are bothered about soil alkalinity or acidity, unless it is massively one way or the other.

Thanks Owdboggy...off to buy some phlox :)

There is a huge selction of them to be had. Best red is one called Oxblood (or German equivalent).

Wow, just seen the red one in google images and it looks amazing. I want to plant it in the base of my container that is currently housing a standard azalea which flowers pink so one that doesn't clash with a bright cerise pink would be perfect.

If not then either White Admiral or White Icicle are good clean white ones.