These tall perennials from China and Japan are often still listed under Bocconia, a name properly belonging to their shrubby tropical relatives. Tall, branching stems carry clouds of tiny flowers. Leaves are large and deeply lobed. The plants look tropical, and their garden value lies in size and structure rather than floral impact. Spread by creeping rhizomes and can be invasive if not controlled.Macleaya cordata
Grows to 7–8 ft. tall and 3 ft. wide, with grayish green, 10-in. leaves. White to beige flowers. Is considered less invasive than M. microcarpa.
Native from central Europe to Siberia. To 1 1/2 ft. high, 1 ft. wide. Pale blue or white flowers ...
Plants and flowers resemble those of medium-size campanulas. Blue or white, drooping, bell-shaped flow...
Native from western Europe to the Caucasus and Turkey. Forms a dense clump 8–18 in. high, spread...