One of my favorites, the Balloon flower (Mariesii) Platycodon grandiflorus. My yard is filled with them. Northeastern Pennsylvania. A notable feature of the plant is the flower bud which swells like a balloon before fully opening. They
have gained the Royal Horticultural Society’s Award of Garden Merit.
They bear two- to three-inch balloon-shaped buds that open to bell-shaped flowers with five points, in pink, blue, and white. The five petals are fused together into a bell shape at the base Then burst open and resemble a star.