These are well-behaved, long-lived, relatively small shade trees; make fine street or lawn trees. Growth rate is slow to moderate. Very hard, tough wood. Dark green, sawtooth-edged leaves color up agreeably in fall in the Upper, Middle, and Lower South, hang on late in season. Fruits (small, hard nutlets in leaflike bracts) are carried in attractive drooping clusters to 5 in. long. Mature trees need little or no pruning.
C. betulus. EUROPEAN HORNBEAM. Zones US, MS, LS; USDA 6-8. Native from Europe to Iran. Excellent landscape tree to 40 ft. tall. Dense pyramidal form, eventually becoming as broad as tall, with drooping outer branches. Often sheared into a hedge in Europe. Handsome, furrowed gray bark like that of C. caroliniana. Leaves seldom marred by insects or disease, 25 in. long, turn yellow or dark red in autumn. Best in full sun but tolerates light shade. 'Emerald Avenue' is a vigorous grower with a pyramid shape and good heat tolerance. 'Fastigiata' is the selection commonly sold; tree develops an oval-vase shape with age.
C. caroliniana. IRONWOOD. Zones US, MS, LS, CS; USDA 6-9. Native from Nova Scotia to Minnesota, southward to Texas and Florida. Also known as blue beech and musclewood in its native range, where it is often found at forest edges or as an understory plant along rivers and streams. Those common names refer to the tree's trunk, which is blue-gray and smooth, with undulations that look like muscles flexing beneath the surface. Grows to 2530 ft. tall and wide, with round head; can be grown as single- or multitrunked tree. Leaves, 13 in. long turn mottled yellow and red in fall; they drop before those of C. betulus. Ironwood does well in a range of exposures from full sun to heavy shade. Best in natural gardens. 'Native Flame' has good form and dependable red fall color.