Can you scrape away enough soil/mulch, whatever that is, down to the grass level or slightly below if you want to use a layer of mulch again. Sink the shrubs correspondingly lower. Banked up soil will do a number on your house's wood. Get rid of the timbers and do a simple trench edge - tools needed would be a sharp flat head spade and a hoe to smooth out the edge.

Lots of trench edging tutorials on the internet. Always looks neat and once accomplished it's easy to get out any grass that might encroach on the trench.

I "second" duluth's suggestion. It doesn't look like there needs to be a retaining wall. Reduce the height a little and blend the grade. Not only would it be good to reset the plants at slightly lower elevation, but they're too close to the house, too. They should be 30" off the wall, not 12", so there's a second reason to re-do them.

You could do it even with rock.

{{gwi:36686}}

cinder block is cheap and so is paint :). I was wondering the same thing recently and Deviant/Karen helped me out with the idea of doing a tiled mosaic on the cinder block. I agree, plantings are far too close to the house, easy fix would be get some metal landscape stripping to get it off the house.