This is Geranium "Rozanne". I bought and planted it last year--talk about a garden workhorse. This is its first bloom of the season. Little did I know that it was awarded the 2008 Perennial Plant of the Year by the Perennial Plant Association. I did not even know such a group existed but I'm glad they do. You see, the organization gives its highest award to the perennial that successfully meets the sort of criteria that I'm always looking for. That is, a plant that survives in a wide range of climatic conditions, is low maintenance, is pest and disease resistant, and has multiple season ornamental interest.
Rozanne is a hardy (to zone 5), repeat blooming geranium. The violet-blue bloom is about 2 inches across. It likes full sun to part shade. Mine gets part shade because it's planted underneath a huge oakleaf hydrangea and butterfly bush. It grows to about 20 inches high and is exceptionally heat tolerant. It blooms all summer and shearing it mid-summer will encourage repeat blooms.
As soon as I finish this post, I'm going to the Perennial Plant Association's website to see other award winners. I love that they've done all the hard work for me.
Bookshelf: Container Gardening Books