I took my dremel to the edges of the wall to sand them straight. Then I cut away some of the bricks so their individuality is more apparent, and also to avoid the implication that the edge was the actual end of the wall, not just the edge of the scene. My husband thinks it looks bombed out now, so maybe I went too far?
For the dirt, I used a mix of watered-down craft glue, flour, and sand. I put sand in the planter, and primed and base coated the foliage.
Then I stained the base, which looks horrible. I must have gotten putty and/or glue on the wood in a few places, because the stain went on really blotchy. It’s also just really soft cheap wood. I’ll paint over it later.
I thought the plant leaves turned out well enough, so I made a couple large ones that can hang over the wall, like there’s a palm tree that leans over the house. I’ll paint them and see how they look before gluing them on.