Leafy, clump-forming perennials related to penstemon. All are native to the eastern U.S. and grow in damp places in sun or light shade. Frequently used in bog gardens. All bloom in late summer and autumn. Common name comes from the oddly formed flowersinch-long, puffy, and two-lipped, with a fancied resemblance to a turtle's head. Useful for cut flowers, shade gardens, wild gardens.
C. glabra. WHITE TURTLEHEAD. Grows 23 ft. tall (occa- sionally much taller), 112 ft. wide. Medium green leaves to 8 in. long; white or palest pink flowers. 'Black Ace', with white blossoms, typically grows 34 ft. tall but can reach 6 ft. Its leaves emerge deep green with an almost black cast, then lighten to green by late summer.
C. lyonii. PINK TURTLEHEAD. Zones US, MS; USDA 6-7. Reaches 34 ft. tall, 2 ft. wide. Dark green, 4- to 6-in.-long leaves; rose-pink flowers. 'Hot Lips' has red stems and reddish purple flowers with a spot of white at the base. 'Pink Temptation' grows just 15 in. tall; flowers are dark pink.
C. obliqua. ROSE TURTLEHEAD. Grows to 2212 ft. tall, 1 ft. wide. Dark green leaves to 8 in. long; deep pink blossoms. Latest bloomer among the species listed here.