American hornbeam

American hornbeam: how do you recognise it?

Habit

Small, spreading tree or large shrub, about 9 m tall and 8 m wide; slow-growing.

Trunk

Smooth, blue-grey and fluted with muscle-like bulges, very decorative in winter.

Leaves

Oval, 6–12 cm, doubly toothed with prominent veins; dark green, yellow to orange-red in autumn.

Flowers

Catkins in April–May, male and female on the same tree; not showy.

Fruit

Small nutlets in three-lobed, leafy bracts, hanging in clusters.

Flowering: April–May · Plants: March–April and October–December · Pruning: February

Why grow it?

• Distinctive blue-grey, fluted trunk with muscle-like ridges that stands out all year.
• Lovely autumn colour from yellow to orange-red.
• Tolerates partial shade and moist soil, where many other trees grow poorly.
• A small tree that fits a woodland edge or a smaller garden.
• The fruits and buds are a food source for birds.

American hornbeam: where does it grow best?

• Partial shade to shade; it colours best in a bright spot but tolerates a lot of shade.
• Moist, humus-rich soil: sand, loam or clay, acid to neutral.
• Normal to wet soil, including beside a stream or pond; it tolerates temporary waterlogging.
• Plant 4–6 m from buildings or other large trees and let the crown spread up to 8 m wide.

Light

Sun, partial shade and shade

Soil type

Sand, loam or clay

Acidity

Acid or neutral

Moisture

Normal or wet

Size

9 m tall, 8 m wide

Hardiness

Hardy (to -35 °C)

Goes well with

• Ferns: A fresh woodland underplanting that tolerates shade and moist soil.
• Hosta: Large leaves for a shady edge.
• Wood anemone: Flowers in spring before the leaves open.
• Rhododendron: Likes the same moist, acid soil and light shade.

American hornbeam: when and how to plant it?

Plant in March–April and October–December.

1. Plant in March–April or from October to December, when the soil is neither frozen nor waterlogged.
2. Dig a hole twice as wide as the root ball and just as deep.
3. Set the tree at the same depth as in its pot or at the nursery and backfill with the soil you dug out, mixed with a little compost.
4. Add a stake and tie the trunk loosely with a tree tie.
5. Water generously straight away and spread a 5–8 cm layer of leaf mould or wood chips around the base.

Care

Water

In the first two summers, water thoroughly every week in dry spells. Even an established tree appreciates water in a prolonged dry period.

Feeding

Usually unnecessary. A layer of compost in spring is enough.

Mulching

Leave fallen leaves in place or spread leaf mould around the base: it keeps the soil cool and moist.

Staking

Tie a young tree to a stake for 2–3 years and check the tie every year.

Training

In the first years, choose one or a few strong stems; after that it shapes itself nicely.

Tip: Put it in partial shade on moist soil, for example at a woodland edge or in a shady corner, and leave it in clear view in winter: that is when the remarkable trunk looks best.

American hornbeam: when to prune it?

Pruning months: February.

When: It needs little pruning; if needed, in winter, in January–February, when the tree is bare.

How:

• Remove dead, damaged and crossing branches.
• Cut small branches just outside the branch collar, never flush with the trunk.
• On a young tree, remove competing leaders and keep a single main leader.
• Never remove more than a fifth of the crown in one year.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Seed

Sow the seed outdoors in autumn in a tray of light, moist soil, or after cold stratification in spring. The seed may lie dormant for a year before germinating.

Nursery

Seedlings grow slowly. For a handsome tree quickly, buy a young tree from a nursery.

American hornbeam: how does it get through the winter?

Hardy to −35 °C.

• Fully hardy, to about −35 °C: no protection is needed in Belgium.
• In winter the smooth, fluted trunk is an attractive focal point.
• In a hard winter, give young trees an extra layer of mulch around the base.

Diseases and pests

• Scorched leaf edges: Brown edges in drought or on a spot that is too sunny and dry. Water generously and apply a mulch.
• Powdery mildew: White powder on the leaves, mostly at the end of summer. Usually harmless; choose an airy position.
• Aphids: Sticky leaves in summer. Ladybirds and tits usually clear them up.
• Coral spot: Orange-red dots on dead twigs. Prune affected branches back into healthy wood.

Through the year

• February: Prune if needed. Remove dead branches.
• March: Plant. Apply mulch.
• April: Catkins open. Planting still possible.
• May: Leaves fully out. Water in dry weather.
• June: Water young trees in dry weather.
• July: Water during prolonged drought.
• September: Fruit ripens. Collect nutlets for sowing.
• October: Autumn colour from yellow to red. Plant.
• November: Plant. Leave the leaves as mulch.
• December: Rest. Plant while the soil is open.

Good for wildlife

Birds

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

Did you know?

• In English the tree has nicknames such as musclewood and blue-beech, after its muscular, blue-grey trunk.
• The wood is hard and dense and was once used for tool handles and implements.
• It is related to our native hornbeam, but stays smaller and tolerates more shade.