Posted: 07/05/2017 at 09:14
Three decent clematis would do the job, or four if you had a couple of alpinas in there. Many are perfectly happy in a northerly aspect. If you choose carefully, you can have colour there most of the year.
Hydrangea would be perfect though. There is an evegreen one whose name I've forgotten but petiolaris is hard to beat, I think.
I quite like your wall. Leaving some on show is actually a nice backdrop. You could use a few evergreen shrubs for all year interest, with a few climbers in behind, instead of just climbers. How much room do you actually have at the base for planting though? It'll be very dry there anyway, so you'll need to improve the soil a good bit.