Hornbeam

Hornbeam: how do you recognise it?

Habit

Tree of 15–25 m with a broad, dense crown about 12 m wide; often grown as a clipped hedge, pleached tree or coppice.

Leaves

Alternate, oval and pointed, 5–10 cm, sharply double-toothed, with 10–15 pairs of parallel veins between which the leaf is pleated. Yellow in autumn.

Bark

Grey and smooth, with twisting ridges as if there were muscles underneath. Buds pointed and pressed against the twig.

Flowers

Catkins in April–May, with the leaves: hanging male catkins and small, green female ones at the tips of the twigs.

Fruit

Nutlets on a three-lobed wing, in hanging clusters.

Difference from beech

Beech has an untoothed leaf edge and long buds that stand away from the twig.

Flowering: April–May · Pruning: June–September and November–February

Identify by feature: Winged seeds

Looks like it, but isn’t

• Beech Fagus sylvatica: untoothed leaf edge and long buds that stand away from the twig. Difference from beech

Why grow it?

• One of the best hedging plants: dense, tolerant of clipping and tough, even on heavy soil and in shade.
• As a hedge it often keeps its dead leaves until spring, so you still have some shelter in winter.
• Dense hedges are nesting and hiding places for small birds.
• Native, hardy and seldom troubled by disease.
• Suitable for pleached trees, arbours and tunnels.

Hornbeam: where does it grow best?

• Sun, part shade or shade: it is one of the few hedging plants that stay dense in shade.
• Almost any soil that isn’t too dry: sand, loam and heavy clay. On heavy, wetter soil it does better than beech.
• A dense crown casting deep shade: under a free-standing tree only shade plants will grow.
• As a free-standing tree, allow for 15–25 m in height and 12 m in width: something for a park or a large garden. As a hedge you keep it as tall and narrow as you like.

Light

Sun to shade

Legal basis

Any garden soil

Moisture

Normal

Size

20 m tall, 12 m wide

Hardiness

Throughout Belgium, no protection needed

Goes well with

• Beech: Together a mixed hedge: beech for its glossy leaves, hornbeam for the heavier or shadier stretches.
• Field maple: Another native hedging plant that takes clipping well, with yellow autumn colour, for a varied hedge.
• Hawthorn: Thorny and flowering in May: makes a mixed hedge even denser and richer for birds and insects.
• Lesser periwinkle: An evergreen ground cover with blue flowers for the shady foot of a hedge.

Good and bad companions

Goes well with

• Together a mixed native hedge, good for birds and insects: hawthorn, blackthorn, hazel, dog rose, common dogwood, guelder rose, wild privet, field maple
• Tolerate the shade under this tree: oregon grape, rhododendron, oleaster, japanese skimmia, garden privet, camellia, laurustinus, box-leaved honeysuckle

Best kept away from

• Sun-loving plants get too little light under the dense crown: english lavender, heather, butterfly bush, blackthorn, highbush blueberry, sea buckthorn, japanese rose, broom

Hornbeam: when and how to plant it?

1. Plant from November to March when the ground isn’t frozen; for a hedge, bare-root forestry transplants are the cheapest option.
2. For a hedge: about 3–5 plants per metre, in a single row, or staggered in a double row for a wide, dense hedge.
3. Loosen the soil along the whole length of the hedge beforehand and work in some compost.
4. After planting, cut back the tips and long side shoots by a third: the hedge will then branch from the base.
5. Water after planting and during dry spells in the first two summers.

Care

Watering

In dry spells for the first two years; rarely needed after that.

Feeding

A layer of compost in spring keeps a hedge dense and green; no more is needed.

Hedge shape

Clip the hedge wider at the bottom than at the top, so light reaches the base and it stays dense low down.

Birds

Before each trim, check that no birds are nesting in the hedge.

Tip: Want a native hedge that still gives some shelter in winter? Choose hornbeam: the dead leaves often hang on until spring, and it also grows on wet, heavy soil where beech struggles.

Hornbeam: when to prune it?

Pruning months: June–September and November–February.

When: Clip a hedge in late June and/or late August. Prune a tree or coppice in winter.

How:

• Clip a hedge once or twice a year; with a trim in late August it stays crisp until spring.
• It tolerates hard pruning: a neglected hedge can be cut back hard in winter, if need be one side a year.
• On a free-standing tree, remove dead, crossing and low branches in winter, just outside the branch collar.

Caution: Don’t clip a hedge while birds are nesting in it: look carefully between the branches first.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Sowing

Collect the nutlets in autumn, when the wings turn brown, and sow them outdoors in a tray or seedbed. They often only germinate in the second spring.

Self-sown seedlings

You sometimes find seedlings under a hornbeam: move them in winter. For a whole hedge, buying forestry transplants is a better bet.

Hornbeam: how does it get through the winter?

Hardy throughout Belgium: no protection needed.

• Fully hardy.
• A clipped hedge often keeps its dead, brown leaves until the new leaves open in April–May.

Diseases and pests

• Bare base: A hedge that is wider at the top than at the bottom goes bare at the base. Clip it narrower towards the top and, if necessary, cut it back in winter.
• Brown leaves in summer: On a young hedge usually caused by drought. Water during dry spells in the first years, thoroughly rather than often.
• Caterpillars in spring: Caterpillars, of the winter moth among others, eat the young leaves in April–May. A healthy hedge recovers on its own, and tits eat lots of caterpillars.
• Aphids: Sometimes aphids on the young shoots. Ladybirds and birds usually deal with them.

Through the year

• January: Prune a tree or coppice; cut back a neglected hedge hard.
• February: Last month for winter pruning; plant a hedge in mild weather.
• March: Last month for planting bare-root plants.
• April: The leaves open and the catkins flower; the dead leaves fall.
• June: First trim of the hedge in late June; check for nesting birds first.
• July: Hedge trimming still possible; water young hedges in dry spells.
• August: Second trim in late August: the hedge then stays crisp until spring.
• September: Last month for trimming the hedge.
• November: Planting season; winter pruning of trees and coppice starts.
• December: Prune a tree or coppice; plant a hedge in mild weather.

What can you use it for?

Garden and landscape

One of the best hedging plants, even on heavy soil; suitable for pleached trees and arbours.

Wood

Very hard wood (‘ironwood’) for hammer handles, chess pieces and chopping blocks; excellent firewood.

For wildlife

Dense hedges are nesting and hiding places for small birds.

Good for wildlife

Birds

Berries, seeds or insects as food, or a place to nest.

Caterpillars

Host plant: caterpillars of butterflies or moths eat the leaves.

Hedgehogs

Shelter and a layer of leaf litter full of insects.

Did you know?

• As a hedge, like beech, it often keeps its dead leaves until spring.
• The wood is so hard it is called ‘ironwood’: it was used for hammer handles, chess pieces and chopping blocks, and it is excellent firewood.
• Despite its resemblance to beech, hornbeam is not related to it: it belongs to the birch family, like hazel and alder.
• Because it is so hard, hornbeam wood was once used for the wooden teeth (cogs) of gear wheels in windmills and watermills.
• In French, a hedge, alley or arbour of hornbeams is called a ‘charmille’, a classic feature of formal French château gardens.