Hardy Plumbago. The name doesn't sound very interesting, but it is an impressive ground cover providing wonderful color from spring through fall.
Hardy Blue Plumbago, also known as Dwarf Plumbago and Leadwort, Ceratostigma plumbaginoides, Plumbago larpentae, Plumbago larpentiae, produces bright blue flowers atop low-growing, semi-evergreen plants. With a touch of cold weather, the foliage turns to rich scarlet, burgundy or bronze, so there is ornamental interest spring to fall.
Plumbago is most effective as a ground cover, especially under small trees and in bulb beds.