I have a low bank in the garden that Is made up of stone/soil/rubble. A garden designer has suggested we put a gravel path leading to a seating area with grasses/drought tolerant plants down one side (the other side drops down with a small dry stone wall). I'm unsure as to what types of grasses/plants to plant and when.... I've read on the rhs website that some are cld climate grasses and some... What do we live in???