looking for a moss rose with the largest flowers. Need to ring a fountain on a patio. so shallow root is a must. replacing nasturtiums with summer blooms & need that WOW factor that the large flowers would provide. Any other suggestions would also be appreciated but really hoping to find the right low growing portulaca or moss rose with exceptionally large flowers........I'm in S.W. Fla so zone is always an issue. Any help is greatly appreciated............