Allium stellatum. Behaves similar to its cousin, nodding onion, but by the height of summer, the flowering stem of Allium stellatum pulls itself upright to proudly wave its small flower buds. Well-suited to rock gardens and dry-mesic areas like rock outcroppings, Prairie Onion prefers full sun and dry conditions.
More info: https://www.minnesotawildflowers.info/flower/prairie-onion