At the lake on a slope that the roll-in section of the dock gets rolled up onto for the winter I have Geranium Sanguineum. In the spring it's trampled on by everyone when putting in the dock and again when removing in the fall. Even where the tire wheels sit all winter it survives. Its neglected most of the summer and it is thick, blooms, and looks good. It receives partial sun off and on during the day and is Very fragrant. Might be a bit taller (12-15") than you're wanting, but it has nicely survived.