Of all the wall shrubs, Pyracantha is probably the most used. It is evergreen and produces white flowers in late spring, followed by sparkling berries. Here the Pyracantha has been carefully trimmed to link with the formal, minimalistic garden design. For a softer look, evergreen wall shrubs can be interplanted with climbers such as summer-flowering clematis or the herbaceous perennial Tropaeolum peregrinum, the 'Canary Creeper'. If you are planting a shrub-climber combination, make sure that the climber isn't too vigorous or it will overwhelm the shrub.