A mix of purple with the green foliage make a statement "Look at me". It's hard to tell in the photo, but for the purple color you could use Mexican Heather, Russian Sage, Lavender, or numerous other Sage plants.
Looking for a new look for your fence? What about the gabion stone fence? I’ve always loved the look of gabion walls – the subtle variation in stone colour, the texture of different rock fillings and the light and shade of stone and crevice.