Geranium pyrenaicum "Bill Wallis" (Mountain Cranesbill)
This hardy, easy to grow Geranium grows to about 15 inches high by 20 inches wide (at maturity) and is literally covered in small, violet blue, blooms for months on end. Given a good shearing after blooming, it is said to spring right back for another show. This clump-forming perennial is slug, deer, and rabbit resistant; bees love it; and it is evergreen and drought resistant. Whew, that's a lot! It also self-sows and for some folks, that may present a problem, but not for me. Zones 5-9, Sun/part shade.