My cousin Janie lives 110 miles northeast of Oklahoma City in Tulsa... in zone 6B... and she is a very hands-on gardener.

The side "yard" measures, I believe, three feet or slightly less. Rather than abandon it to gravel or mud and the gradual accumulation of litter and debris from Oklahoma's seemingly ever-present winds... she laid stepping stones and interplanted them with Mondo Grass. Then, for a bit more visual interest, she put in a couple of clumps of tall Phlox that tied in with the corner planting... a few Bearded Iris that don't bloom much but provide foliage contrast... and a few Hostas.
Just outside her kitchen window she let English Ivy climb the wood fence to soften the look of it.

Instead of a long, narrow, boring "tunnel" between the wall and fence, she created a pleasing, low maintenance garden space.