'front border' plant for partial sun location, mid-Atlantic
I am looking for a "front border" plant for the front 2 to 3 feet of a 22 ft wide x 10 ft deep bed on the side of a townhouse, filled with a variety of native shrubs and perennials. The front part of the bed was starting to look messy and poorly maintained, because of too many different plants crowded together. I decided that the best solution was to clear out the front and replant with (possibly) only one plant, aiming for a more uniform appearance. Actually, I did leave one thing in the "front border" area, a group of Zizia aptera (heart-leaved golden alexander).
# 2 feet tall or less
# tolerant of partial sun / light shade (there is clear sky directly overhead, but the hours of sun are limited by townhouses and trees surrounded the bed, so it is almost like a small interior courtyard)
# preferably spring flowering (for variety, because the taller perennials in the middle and back are summer flowering)
# average, silt loam soil, medium moisture (doesn't have to be drought-tolerant because bed has a drip irrigation system), almost neutral pH (6.8)
# some spreading is good, to fill in the area, but doesn't need to be a very fast spreader
# native to mid-Atlantic region (PA - MD - VA)