European Hornbeam

(Betulaceae - Birch Family)

Form

• medium-sized ornamental tree
• the rarely available species form matures at 40' tall by 30' wide, while the common cultivars are more compact
• species form and cultivars have an upright oval growth habit in youth, becoming more spreading with age
• medium growth rate

Culture

• full sun to partial sun; prefers a moist, well-drained soil but otherwise is adaptable to various soils, soil pHs, heat, and drought
• species form is propagated by seed or rooted stem cuttings; cultivars are usually propagated by rooted stem cuttings or cuttings grafted onto seedling rootstock
• Birch Family, with no significant diseases, and with borers being the primary pest problem; in addition, mature specimens of 'Fastigiata' often exhibit the eventual decline and dieback of the centermost co-dominant branches, possibly due to self-girdling that brings both abiotic and biotic stresses upon the tree
• the species form is rarely available, but the two most common cultivars are commonly available in ball and burlap form
• both the species form and 'Fastigiata' can be limbed up (if desired) very early in youth to at least three feet so that either turfgrass or an ornamental plant bed can be grown underneath; however, as the tree matures and casts a dense shade, turf will tend to die out underneath and only shade-tolerant plants will grow at the tree's base
• European Hornbeam is somewhat sensitive to being transplanted in Autumn, and care should be taken to amend the soil, fertilize, water thoroughly, mulch adequately, and avoid Winter salt spray, to enhance survival chances during the first Winter

Foliage

• leaves are alternate, ovate to oblong, about 4" long and 1.5" wide, doubly serrated, with impressed veins
• fall color is a poor chartreuse in many years, but golden-yellow in good years

Flowers

• monoecious (separate gender flowers are produced on the same tree), in pendulous catkins that are both staminate (male, 1.5" long) and pistillate (female, 3" long), produced in April before the foliage and swaying in the Spring breezes, with the pistillate catkins emerging from a pair of three-lobed bracts that are persistent

Fruits

• light brown nutlets, maturing in October, with the enveloping three-lobed bracts appearing as tripartite umbrellas over them
• semi-showy bracts change from light green to pale yellow in September, and are clustered on the twigs

Twigs

• olive-brown and lenticeled, with prominent axillary Winter buds that are long and partially curving around the twigs

Trunk

• smooth and steel gray, sometimes having a rippled muscular character to its surface

ID Summary

• pendulous catkins are produced in early Spring, emerging from showy bracts that are persistent into Autumn, followed by oblong leaves that are doubly serrated and alternate; many branches occur low and in semi-whorled fashion on the trunk of the tree (for the species form and 'Fastigiata'), curving outward initially, then ascending rapidly, with relatively little branching, for a very straight, vertical, and semi-formal architectural appearance, with Winter buds that partially curl around the young twigs; 'Columnaris' is higher-branched, of much less caliper, and more stately, with a more even distribution of the branches up and down the central leader

USAGE

Function

• specimen or focal point tree of great symmetrical and architectural value; can also be an effective year-round deciduous screen or tall, wide hedge when used in rows
• various cultivars are refined (in terms of shape and density for formal appearance) to the point that they are excellent to use in formal situations, especially 'Columnaris'

Texture

• medium-fine texture in foliage and when bare
• thick density in foliage and when bare, with many ascending bud-laden twigs and branches forming a thick canopy even in Winter (a "deciduous screen")

Assets

• perfect formal symmetry
• distinctly ascending habit
• ornamental Winter buds, Spring catkins, and Autumn fruit bracts
• smooth gray bark, sometimes muscled
• fine-textured branches and twigs
• the species form and 'Fastigiata' may serve as a dense, tall privacy screen when in foliage, and a semi-privacy screen in Winter (rare for a deciduous tree)
• 'Columnaris' is stately and extremely formal-looking, with a limbed-up trunk, strong central leader, and branches arranged tightly near the trunk

Liabilities

• 'Fastigiata' and the species form get wide with age (especially near the base) and may also exhibit central canopy decline and dieback with age
• borers may infest the trunks and branches of all forms of this species with age

Habitat

• zones 4 to 7
• native to Europe and Asia Minor

SELECTIONS

Alternates

• trees with a wide teardrop shape and ascending branches(Pyrus calleryana 'Bradford')
• trees with smooth gray bark (Amelanchier laevis, Carpinus caroliniana, Fagus sylvatica, Fagus grandifolia, etc.)
• trees with unusual fruits (Asimina triloba, Halesia carolina, Koelreuteria paniculata, Ostrya virginiana, Staphylea trifolia, etc.)

Variants

• Carpinus betulus 'Columnaris' - a distinctly upright columnar to narrow teardrop growth habit through maturity, densely foliaged, a much thinner version of the species (to 25' tall by 10' wide, but often seen at half to two-thirds of that size), noted for its dark green Summer foliage that clusters at the branch tips, and especially noted for its formal aristocratic appearance, with small branches continuously emerging along the length of the strong central leader that is limbed up 3' to 5' during nursery growth and therefore does not branch and foliage to the ground; a great architectural small- to medium-sized tree for complementing either tall buildings or buildings with strong vertical lines
• Carpinus betulus 'Fastigiata' - the most common form available, being somewhat smaller than the species (to 30' tall by 20' wide, but still relatively large in its own right, appearing very "full" due to its dense branching) but distinctly spreading with age (it is teardrop in shape, not fastigiate, although there is probably more than one form of 'Fastigiata' in the nursery trade); a liability is that the central co-dominant branches may eventually decline and die, possibly due to being self-girdled by the many closely-packed competitive side branches that emerge from virtually the same point (reminiscent of Pyrus calleryana 'Bradford'), eventually leading to central wood decay and pest/pathogen invasion

NOTES

Translation

• Carpinus is the classical Latin name for this tree.
• betulus means "like Birch", referring to various morphological traits that this tree and other members of the Birch Family possess.

Purpose

• European Hornbeam, in its various cultivar forms, is a tree that always has a tight, formal, perfect symmetry and a fine-textured, ascending, densely twiggy year-round appearance.

Summary

• Carpinus betulus is a columnar or teardrop-shaped tree with two primary cultivars, both noted for their fine and dense texture, ornamental smooth gray bark, dense Summer foliage, pendulous Spring catkins, and unusual Autumn fruits.