How much sun and when? If it's morning sun or filtered afternoon sun, an azalea planted on a 6-8" layer of rich, well-draining humus soil would work. Azalea's have a platter root system...shallow but wide spread. Evergreen and bloom 2-3 weeks in spring...depending on weather and variety.
With a little amending of the soil, Nandina "Firepower" will give you year around color, no blooms but tons of color.