If you had a retaining tire wall.

Our finished floor level is lower than the ground level at the back of the house. As we discovered yesterday while studying plans. Also it’ll be very visible from our living room.

The floor level of my house is below ground level on one side of the house - the garden side.

I have no doors onto the garden at the moment...my kitchen extension will have doors onto the garden but they will open up onto a sunken patio - retaining wall all around...steps upto the garden. Not ideal but I was fed up with walking round the house to access the garden.

Have you looked at snow in summer? It's not a gorgeous plant by any means, but it's a mat forming perennial- it has silvery green foliage with masses of white flowers in Late Spring/Early Summer. Little maintenance other than cutting off what you don't want, trim the flowers off when they are dead. 
I stick it in my stone wall to fill gaps. It's drought tolerant. And that foliage is fab in the winter.
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