Frankly, don't touch it. THAT is the style of this house and it looks an architectural piece. I love the colour and the way seamless manner in which the colours all seem to blend.

I agree that that stone wall is difficult. Nothing is going to grow in it. My suggestion would be to even up the wall so it is level, and fill with it with grey gravel (colour of your roof) and then add a Japanese rock formation - no plants necessary

or you could add a water feature that is very very understated in the middle


On the other side I would pump up a Japanese garden theme and plant azaleas (you need to install special earth for them if your soil is sand/chalk), camelias, some Iris bulbs, add a dwarf Japanese maple or two (one in red leaf and the other in green) a few more rocks.

Seriously lovely home.