Hedge for a poorly drained shade

At the bottom of our garden we have a very ugly north-facing wall. The area is very shady and poorly drained. We have tried to put some hedging laurus, but they miserbly died. What can we do? How the drainage can imporved? I have browsed the RHS plant search and I don't see any hedging that has all the above charcterisitcs: shade tolerant, north facing, porrly drained... 

Thanks!