Carpinus betulus – Common Hornbeam (= C. caucasica) (central Europe)
Habit: Medium-size tree, 5-15 (20) m tall, 4-6-8 m wide depending on whether it has several stems, somewhat asymmetrical, with one or more stems, crown usually ovoid, stem crooked, branches vertically upright, twigs extended, horizontal to slightly lilting, slow to moderate growth, 20-40 cm a year.
Flowers: Monoecious, few conspicuous, yellow catkins during shooting in May.
Leaves: Elliptical, dark green, yellow-brown in October, occasionally yellow-orange or green-yellow, often persistent and brown into spring.
Roots: Intense, dense cordate root system, sensitive to compaction and floods.
Demands: Sun to shade, cool to warm areas, tolerates heat if soil is moist enough, frost hardy, tolerant of urban pollution, wind resistant.
Soil: Moderately dry to fresh; on all soil that is not too poor, sensitive to salt..
Note: Takes very well to cutting; traditional plant for historic gardens.
Though the common hornbeam is widely used as a typical hedge, it has much potential for design due to its excellent tolerance of cutting. Its ability to regenerate is especially great.
Hardiness: Zone 5b
Also see chapter on topiary plants