I don't know whether any of these will be ok in your zone - check 'em out. My sister has them 3 feet from her IG pool and they get alot of splashing and overflow, hasn't killed them yet.

Plumbago (flowering)
"trinette schefflera" or dwarf arborcola (trained as hedge or bush)
variegated ginger
lantana (flowering)
eugenia myrtifolia (trained as hedge or bush)