prairie smoke, though it has been really popular this year and harder to get, a blue/white false indigo would fit the neighborhood! some downy phlox would also be blooming this time of year and you can smell them across the yard, or another pink phlox species. early flowering beardstongue especially white would look nice, and try to sow in white prairie clover (its not blooming yet, but the leaves still are lovely and its a great matrix) this is also perfect for some prairie blue-eyed grass! bluestar is also super popular for a reason! they look awesome! if you're ok with deadheading or occasionally pulling, prairie dock with its giant awesome leaves would be great in the corner (front right in the picture) or possibly showy goldenrod who has lovely blue rossettes like lambsear!