Planting for the "third dimension", height, really allows all the space within the patio or courtyard to be used to the full, and the added heat retained by a south- or west-facing wall will protect more tender and exotic plants.
Planting Ideas
Having a wall to plant against adds a whole extra dimension to your possibilities, especially if it faces south or west, because the heat from the sun is absorbed during the day and given off overnight. Nearby plants will be kept several degrees warmer than those beyond the wall's influence. This allows the planting of subjects that could not survive without the extra heat.
Most shrubs can be grown near a wall. Wall-shrubs are specifically those that can be pruned back to form a covering for the wall, supported against it using wires and ties, and through which other plants such as climbers can be grown. Climbers support themselves in a number of ways: by twining their stems around a support; by twisting tendrils or leaf-stalks around a support; by using thorns to scramble; or by the use of aerial roots or sucker pads to attach themselves.
Whether the plant is intended for a wall or a pergola, it should be of a size chosen to be in context with its surroundings, otherwise it will need regular pruning to keep it under control, and this may be at the expense of the flowers. Do bear in mind that, after rainfall, the plant will drip for some time, and this may result in the surface underneath becoming slippery. If this is also a well-used route through the garden, it may be advisable to replace a smooth surface, such as decking, with a non-slip one, such as gravel. This can be edged with brick or bonded with resin to keep it from interfering with mowing the lawn.