Ceratostigma plumbaginoides

Plumbago likes to be in a sunny average to dry location. It tolerates some shade, but won't bloom as well. A good choice for poor soils and difficult sites. Looks beautiful in a container or spilling over a wall! Emerges late, end of April here in Pennsylvania.

"Plumbago (also commonly called leadwort) is a wiry, mat-forming perennial which spreads by rhizomes to form an attractive ground cover. Typically grows 6-10" tall on generally erect stems rising from the rhizomes. Oval to obovate, shiny, medium green leaves (to 2" long) turn bronze-red in autumn. Terminal clusters of 5-petaled, gentian blue flowers (1/2" to 3/4" diameter) appear above the foliage over a long summer to frost bloom period. Flowers resemble those of woodland phlox.

Late, long-flowering plant serves as excellent ground cover for sunny to partly shaded areas in the landscape. A good plant for interplanting with spring bulbs because foliage emerges late as the bulb foliage is dying back. Underplanting for shrubs. Edger. May be used in rock gardens or border fronts with careful monitoring of spread. As a ground cover, plumbago would probably be as extensively planted as vinca, pachysandra or English ivy, except for the fact that it lacks their evergreen foliage." - Missouri Botanical Gardens

"Belonging to a group of deciduous perennials and shrubs from eastern Africa and Asia, leadwort is a wiry, semi-woody, mat-forming perennial which spreads by rhizomes to form an attractive ground cover. Like many nice groundcovers, it can be somewhat invasive in optimum growing conditions. These plants add a leafy green texture to the garden in summer, electric deep blue flowers from mid-summer on, and couldn't be prettier in autumn with its reddish leaves. Highly rated as a ground cover, it would no doubt be more popular if it didn't die away completely in winter, leaving bare patches in the garden. Plants are late to emerge in the spring, so their location should be carefully marked to avoid damage from early spring cultivation." - gaygardener.com