You could us any of these: wall shrubs such as herringbone cotoneaster, winter jasmine or Japanese quince, creepers such as ivy or climbing hydrangea and climbers such as roses, clematis or jasmine. Some are evergreen and most flower.
I have 2 walls (13 inches deep, 65 inches high, 230 inches long, second one exact same except 110 inches long). I am looking for something evergreen with flowers some part of the year that would go at least half way up the wall. I dont want any thorns. Also I would need something hardy as I have 2 dogs and no green fingers.
There are wall plants which grow against a wall and may need to be supported, creepers that creep on the wall and attach themselves and climbers that need support in the form of trellis or wires.