Great Groundcover: Cranesbill, aka Perennial Geranium. This pretty, flowering plant comes in pinks and blues, and realm when cut back after blooming. They love partial shade, but will grow in deeper shade. Rich soil and regular fertilizer, regular water and room to spread 24-36" per plant, depending on the variety. Some varieties grow close to the ground, and others to 3' tall.
perennial geraniums - cranesbill - wild geraniums... These are ground cover plants. They grow all over the sand dunes along parts of the Northumberland coast in England UK & are a wonderful sight. They're at home in a windy garden & flower profusely over a long period. You can buy the natural colour pictured, or shades of pink.