This modern wall is beach side. It has two types of plants.
Thread Agave, spiky and modern, natural in arid landscapes.
Standard Mexican Orange Blossom, a traditional shape and species from old world Europe. I imagine the owner wanted something to break up the wall? The planting theme is unclear.
By having a firm design boundaries, and one theme, one of the plant types should go. I have removed the standard topiary and added more of the Thread Agave. If the owner still thinks the wall is still too stark, try a darker natural colour on the wall, or encourage leaves from inside the wall like the Puka leaves.