Carpinus is Latin for “hornbeam;” caroliniana means “of Carolina.”
Hornbeam refers to the dense, horn-like wood, and the use of the wood to make beams and ox-yokes. Other names include blue-beech, ironwood, musclewood and water beech. The tree is called musclewood because the trunk and stems look like flexed muscles.
NATIVE RANGE AND HABITAT
Hornbeam spans an incredible range of latitude, from Ontario across to the vicinity of Quebec City, down through the entire eastern United States to Florida and Texas, then extending in the mountains through Mexico and Guatemala to Honduras. Trees typically grow in coves and along river terraces. It is usually found as an understory tree along rivers and streams throughout its native range where it withstandsperiodic flooding. Trees occur in stream banks, forested wetlands, and other mesic woodlands across Kentucky.
Hornbeam is not ranked as a plant of conservation concern by the Kentucky State Nature Preserves Commission.
Growth Habit and Form
Hornbeam is a small to medium-sized, deciduous tree that is often multi-stemmed. It is a fine-textured and graceful tree. Its trunk and major limbs develop a pronounced taper and spiraling, serpentine growth, making the tree look older than it really is. Trees have a wide-spreading, flat or round-topped canopy. Trees typically grow 20 to 30 feet in height with a similar spread.
The paper-thin leaves are alternate, simple, ovate-oblong and grow up to 5 inches long and about half as wide. Leaves have finely toothed margins and pointed tips. Leaves are dark green in summer and turn yellow, orange, crimson and reddish purple in the fall. Fall leaf color variation may be genetic but possibly is enhanced by environmental factors that affect leaf sugar synthesis and transport.
Flowers are catkins, which are cylindrical, drooping clusters. Male flowers are 1 to 1 ½ inches long. Female catkins are 2 to 4 inches long. Flowers bloom between March and May and are wind pollinated.
Fruit is a small, ribbed, seed-like nutlet that is enclosed by an irregular 3-lobed bract. The 1 inch long fruits are grouped in clustered chains, and they blend in with the foliage. Fruit ripens between September and October and are scattered by birds and wind through the winter.
The bark is smooth, dark bluish gray, and occasionally mottled. The trunk and stems are fluted with smooth, rounded, longitudinal ridges, resembling flexed muscles.
Wild and Cultivated Varieties
‘Ascendens’ – a columnar selection.
‘CCSQU’ (Palisade TM) – a broad upright selection with strongly ascending branches.
Pyranudakus’ – V-shaped with a rounded top.
Hornbeam makes an excellent little shade tree for small yards or intimate landscape areas.
Hardy in USDA Zones 2 to 9. This is one of the most broadly climate-adaptable of all our native trees.
Trees are slow growing, averaging 8 to 10 feet over a 10 year period of time, and seldom live more than 150 years.
Cultivation and Propagation Information
Hornbeam is somewhat difficult to transplant and should be moved balled-and-burlapped or from a container in winter to early spring. Trees grow best in deep, rich, moist, well-drained, slightly acidic soils although trees will grow in calcareous soils and drier sites. Hornbeam loves shade but will become more dense and uniform in a sunny, but moist location. Hornbeam was introduced into cultivation in the early 1800s. Propagate by seed collected in September. Seed need moist stratification at 68 to 86oF for 60 days followed by 41oF for 60 days.
Diseases and Insects
Hornbeam is notable for its freedom from insect and disease problems.
The fruits are particularly favored by ruffed grouse and are sought by finches and wild turkeys as well. In the south the nutlets are an important food for gray squirrels. The many erect branch forks and dense crowns of open-grown trees make them popular nesting sites for songbirds. The wood is a favorite of beaver.
The root environment should be kept moist by selecting an appropriate planting site and by mulching. The roots are sensitive to soil disturbance. Soil disturbance, road salt, air pollution, and hot, scorching conditions make the hornbeam unhappy.
TRADITIONAL AND CULTURAL USES
Native American Chippewa used the tree for tent and wigwam supports.
Pioneers used the hard wood for tool handles, mallets, levers and wedges