At an office I periodically visit in some old mill buildings in Concord, NH, there is a garden in the narrow (12' wide?) N-S corridor between 2 of the buildings. It gets a short period of midday sun (these photos were taken just before 11 am in mid-August) but for most of the day are in shade cast by the buildings immediately to the east and west. I think it's well done, with foliage contrast, almost always something in bloom, and a range of heights, all without encroaching on the public sidewalk. It looks good all growing season, and even during the winter the trellises and climbing hydrangea add interest to what would otherwise be a quite stark environment.

Taken from the south end, which gets sun for much of the day for the first 5' or so.

From the north end you can see the anchoring Hydrangeas, (paniculata/shrub and petiolaris/climbing) as well as more of the varied shade perennials (ferns, hosta, astilbe) along with some annuals added for color.

It's beautifully done, particularly considering the shape and the constraints of being a public space that has issues with water availability, winter salt, and dense shade. I believe it is cared for (and perhaps originally designed and planted by) elderly residents who live upstairs of the ground floor offices.