As a comment about Cranesbill (Geranium Rozanne®)
A sweet and charming cottage garden flower that gracefully weaves its way through whatever is growing nearby. It blooms nonstop with an abundance of simple, wildflowery blooms that are very attractive to pollinators. Color ranges from vivid electric cobalt to hyacinth blue to a more pale lavender-blue depending on temperature and lighting conditions. The flowers can take on temporary pinkish tones when newly planted but the coloring will correct itself as the season progresses. One of my favorites; I will always have space in my garden for 'Rozanne'!
UPDATE 28 June 2013:
What a wonderful plant! I have this plant in full blazing sun, partial shade and almost full shade, and it does surprisingly well in all areas. In full shade, plants are a bit sparser and lankier but still manage to bloom well.
This plant is not a tidy, compact specimen. It is a sprawling weaver that can and should be placed closely among other plants so it can scramble up into them. I happen to love this informal, cottage look.
I lost two of my less established plants over the winter due to severe frost heave. They were unmulched and we had a long and difficult winter with no snow cover and countless freeze-thaw cycles. My other 15 plants returned beautifully and are now larger and more amazingly floriferous than ever.
I have been taking advantage of sales and buying up as many 'Rozanne' as I can find to tuck in throughout my garden. It is non-invasive and non-smothering, and to me it is the perfect garden unifier! It is probably my overall favorite cranesbill.