Wet, clay site help

Hi there

I have a site that is clay, wet and falls on the south side of the corogated fence. It is 1200cm x 70cm and I have espalied limes on the fence which are doing well. The Convolulous that I had underneath and need to replace didn’t like the wet. I would like something in bulk, that is green, grey or white hues and that will grow to max 40cm high or can be pruned. It also lies beside my pool so needs to be able to work with that. Ie not make a mess 🙂
Someone suggested acorus mini green but interested in your thoughts.
Thank you