European white elm

European white elm: how do you recognise it?

Habit

Tree of 20–30 m with a broad, open crown of about 15 m; old trunks often with burrs and buttress roots.

Leaves

Alternate, 6–12 cm, oval with a very lopsided base, sharply double-toothed with forward-curving teeth; upper side fairly smooth, underside softly greyish-hairy. Leaf stalk 4–6 mm.

Bark

Grey-brown, in thin flakes; old trunks often have burrs, epicormic shoots and plank-like buttress roots at the base.

Flowers

Clusters of flowers on long, hanging stalks (1–3 cm), in March before the leaves.

Fruit

Small (about 1 cm) winged fruits with a finely fringed edge, on long stalks; the seed sits in the middle.

Difference from field elm

Field elm has almost stalkless flowers and fruits, a wing without a fringe, and often corky ridges.

Difference from wych elm

Wych elm has a larger, very rough leaf and large, stalkless fruits.

Flowering: March · Pruning: November–February

Identify by feature: Lopsided leaf base · Winged seeds

Looks like it, but isn’t

• Field elm Ulmus minor: flowers and fruits almost stalkless, a wing without fringe, and often corky ridges. Difference from field elm
• Wych elm Ulmus glabra: larger, very rough leaf and large, stalkless fruits. Difference from wych elm

Why grow it?

• An elm you can still plant: not very susceptible to Dutch elm disease.
• Grows well on wet soil and tolerates temporary flooding.
• Food plant of the white-letter hairstreak; old trees with cavities are valuable for birds and bats.
• Flowers as early as March, with gracefully hanging little flowers.

European white elm: where does it grow best?

• Sun to partial shade.
• Moist to wet, fertile soil such as river clay or valley-floor soil; chalk is no problem. Dry sandy soil does not suit it.
• Tolerates temporary flooding: a tree for banks, stream valleys and wet meadows.
• Allow for 20–30 m in height and a crown of about 15 m: only for a large garden, a park or an avenue.

Light

Sun or partial shade

Legal basis

Any garden soil

Moisture

Moist to wet

Size

25 m tall, 15 m wide

Hardiness

Throughout Belgium, no protection needed

Goes well with

• English oak: Together with the European white elm, a tree of the hardwood floodplain forest along rivers.
• Alder: Grows on the same wet soil and also tolerates flooding.
• Guelder rose: White flower heads and red berries in the damp shrub layer.
• Bird cherry: Fragrant white flower spikes in spring, in the same wet woods.

Good and bad companions

Goes well with

• Tolerate the shade under this tree: oregon grape, rhododendron, oleaster, japanese skimmia, garden privet, camellia, laurustinus, box-leaved honeysuckle

European white elm: when and how to plant it?

1. Plant from November to March, when the ground is not frozen.
2. Preferably choose plants of native (local) origin, from a reliable nursery.
3. Tie a young tree to a stake and keep the base free of grass for the first few years.
4. Water after planting and during dry spells in the first summers.

Care

Watering

Rarely needed on wet soil; on ordinary garden soil, in dry spells during the first few years.

Feeding

Not needed.

Epicormic shoots

Cut shoots on the trunk off in winter if you want a clean trunk.

Checking

In June–July, still check whether any branches are wilting: a European white elm can also get Dutch elm disease, although it rarely does.

Tip: Want to plant an elm without a resistant cultivar? Choose the European white elm: it is native, rarely affected by Dutch elm disease and grows where other trees get wet feet.

European white elm: when to prune it?

Pruning months: November–February.

When: In winter (November–February).

How:

• Little pruning needed. Epicormic shoots on the trunk can be cut off in winter.
• Give a young tree a single central leader and raise the crown gradually. Never prune in spring or summer: fresh wounds attract the elm bark beetle.

Caution: Leave the sawing of heavy branches on old trees to an arborist.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Sowing

The fruits ripen in May–June and only stay viable for a short time: sow them straight away, on the surface of moist soil.

European white elm: how does it get through the winter?

Hardy throughout Belgium: no protection needed.

• Fully hardy.
• Winter is when you prune, and when the burrs and buttress roots of old trunks are easiest to see; by March the first flowers already hang on their long stalks.

Diseases and pests

• Dutch elm disease: Rare, but not impossible: branches that wilt in June–July and turn yellow to brown. Have the tree inspected.
• Epicormic shoots: Lots of young shoots on the trunk, especially on old trees or after heavy pruning. Cut them off in winter.
• Drought: On dry soil it struggles and drops its leaves early. Choose a moist spot.
• Leaf galls: Rolled leaves or galls on the leaf, caused by aphids. Harmless.

Through the year

• January: Prune if needed; cut off epicormic shoots.
• February: Last month for pruning.
• March: Flowers on long, hanging stalks; still planting season.
• May: Fruits ripe (May–June): sow straight away.
• June: Look out for wilting branches; do not prune.
• July: Water young trees on ordinary soil in dry spells.
• October: Yellow autumn colour.
• November: Planting season; pruning is possible again.
• December: Prune: cut off epicormic shoots.

What can you use it for?

Garden and landscape

An elm you can still plant: not very susceptible to Dutch elm disease and suited to wet soil and stream valleys.

For wildlife

Food plant of the white-letter hairstreak; old trees with cavities are valuable for birds and bats.

Did you know?

• It is far less affected by Dutch elm disease than other elms: the elm bark beetles that spread the fungus avoid its bark.
• Its fruits have a finely fringed edge: that sets it apart from all other native elms.
• Old trees with cavities and burrs are valuable for birds and bats.