White poplar

White poplar: how do you recognise it?

Habit

Large tree of 15–30 m with a broad, often irregular crown; produces many root suckers and so often grows in groups.

Leaf

Alternate; on long shoots palmate with 3–5 lobes, on short shoots oval with wavy teeth. Underside and young twigs white-felted.

Bark

Whitish-grey with rows of dark, diamond-shaped lenticels; dark and fissured at the base of the trunk.

Flower

Catkins in March; male and female catkins grow on separate trees.

Fruit

Fluffy seeds in May, only on female trees.

Difference from grey poplar

Grey poplar (Populus × canescens) is a hybrid with aspen: less deeply lobed, and grey rather than white felted.

Flowering: March · Pruning: November–March

Identify by feature: Palmate leaves · White or silver underside · White trunk

Looks like it, but isn’t

• Grey poplar (Populus × canescens): a hybrid with aspen: less deeply lobed, and grey rather than white felted.

Why grow it?

• Silvery-white leaves that shimmer in the wind, and a whitish-grey trunk.
• An excellent windbreak on the coast: it tolerates wind, salt spray and poor sandy soil.
• Grows fast and binds sand and loose soil with its roots.
• Grows on almost any soil, from dry sand to damp ground.

White poplar: where does it grow best?

• Full sun.
• Almost any soil, from dry dune sand to damp ground by water; tolerates wind and sea wind.
• Its roots seek out water and can damage drains, land drains and foundations: keep it well away (20 m or more) from buildings and pipes, especially on clay.
• It suckers, even far from the trunk: not next to a lawn, border or patio. It does suit a windbreak on the coast, a park or a large site.

Light

Full sun

Legal basis

Any garden soil

Moisture

Dry to wet

Size

25 m tall, 15 m wide

Hardiness

Throughout Belgium, no protection needed

Goes well with

• Sea buckthorn: A native coastal shrub with orange berries: together a layered windbreak.
• Burnet rose: A low dune rose with white flowers in May–June, for the sunny edge.
• Creeping willow: A low dune willow that helps bind the sand.

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

White poplar: when and how to plant it?

1. Plant from November to March, bare-root or root-balled; young trees establish easily.
2. Don’t plant it in a small garden or close to the neighbours: the suckers don’t respect property boundaries.
3. For a windbreak: plant the trees in a row, with low, wind-firm shrubs such as sea buckthorn in front.
4. Put a stake on the windward side and tie the trunk loosely; on the coast this is essential.
5. Water after planting and during dry spells in the first year.

Care

Watering

Only in dry spells during the first year.

Feeding

Not needed.

Suckers

Mow or cut off root suckers regularly, as close to the ground as possible.

Inspection

Have an old tree near a path or building checked regularly: the soft wood breaks easily in storms.

Tip: Planting a white poplar on a large site anyway? Put in a root barrier straight away on the side facing the lawn or buildings: tackling suckers afterwards is far more work.

White poplar: when to prune it?

Pruning months: November–March.

When: Dead, diseased and broken branches can be removed at any time of year. If pruning is needed, do it during winter dormancy (November–March).

How:

• Mow or cut off root suckers regularly.
• Hard pruning triggers even more suckers: prune as little as possible and only remove dead, broken and obstructive branches.
• Train a young tree on a single leader.

Caution: After a white poplar is felled, new suckers spring up from the roots everywhere: keep mowing them for years.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Root suckers

In winter, cut a sucker with a piece of root away from the parent tree and plant it elsewhere.

White poplar: how does it get through the winter?

Hardy throughout Belgium: no protection needed.

• Fully hardy, even in an open, windy spot on the coast.
• The whitish-grey trunk with its dark diamonds stands out best in winter.

Diseases and pests

• Root suckers: Young shoots in lawns and borders and even between paving slabs, far from the tree. Mow or cut them regularly; with a new planting, a root barrier helps.
• Root damage: Roots in drains and land drains, and cracks in foundations on clay. Plant well away from buildings.
• Branch failure: The soft wood breaks easily in storms, especially on old trees. Have dead and weak branches removed in good time.
• Fluff: In May, female trees produce a lot of fluff, which can fill gutters and ponds. Harmless.

Through the year

• January: Remove dead branches; lift suckers with roots to replant.
• February: Plant bare-root trees; formative pruning in mild weather.
• March: Catkins; last month for pruning and planting.
• May: Fluff on female trees; mow off the first suckers.
• June: Mow off suckers in lawns and borders.
• August: Cut off suckers; water young trees in dry spells.
• October: Leaf fall: rake the leaves off lawns and paths.
• November: Planting season starts; winter pruning possible.
• December: Remove dead and broken branches.

What can you use it for?

Garden and landscape

Windbreak on the coast; its roots bind the sand.

Wood

Light, soft wood.

Caution: Sends up many root suckers in lawns and borders.

Good for wildlife

Caterpillars

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

Did you know?

• Produces many root suckers and so often grows in groups, especially near the coast.
• A group of white poplars is often a single plant: the trees are suckers from the same roots.
• Its Dutch name, ‘abeel’, comes via Old French from the Latin albellus, ‘whitish’.
• The Dutch word abeel comes via Old French from the Latin albellus, ‘whitish’. In English, too, the tree is sometimes called abele.
• Like all poplars, white poplar is dioecious: male and female catkins grow on separate trees.