Osier

Osier: how do you recognise it?

Habit

Shrub or small tree of 3–6 m with long, straight shoots; often managed as coppice or a pollard.

Leaf

Alternate, 10–20 cm long and 1–2 cm wide, untoothed with a slightly rolled-under edge; underside covered in silky, silver-grey hairs.

Shoots

Long, straight and pliable, hairy at first, later glossy greenish-brown.

Flower

Catkins in March–April, before the leaves; male and female catkins on separate plants.

Fruit

Fluffy seeds in May.

Difference from white willow

White willow has shorter leaves (5–10 cm) with a toothed edge, and becomes a large tree.

Difference from goat willow

Goat willow has broadly oval leaves with a grey-felted underside.

Flowering: March–April · Pruning: December–March

Identify by feature: Long, narrow leaves · White or silver underside

Looks like it, but isn’t

• White willow Salix alba: shorter leaves (5–10 cm) with a toothed edge; a large tree. Difference from white willow
• Goat willow Salix caprea: broadly oval leaves with a grey-felted underside. Difference from goat willow

Why grow it?

• Early catkins in March–April: pollen and nectar for bees and bumblebees.
• Gives long, pliable rods every year for weaving, baskets and living willow dens.
• Food plant for many caterpillars and insects, and so food for birds too.
• Grows fast on wet ground, where many other shrubs struggle.

Osier: where does it grow best?

• Full sun; in shade it grows weak and sparse.
• Moist to wet soil: beside a ditch, pond or stream, or in a low, wet part of the garden.
• The roots seek out water: plant it well away from sewers, drains and foundations.
• Allow for 3–6 m tall and about 3 m wide, or keep it small by coppicing it regularly.

Light

Full sun

Legal basis

Any garden soil

Moisture

Moist to wet

Size

5 m tall, 3 m wide

Hardiness

Throughout Belgium, no protection needed

Goes well with

• Alder: A native tree for the same wet bank.
• Guelder rose: Flowers in May–June, bears red berries and also likes moist soil.
• Purple loosestrife: Purple flower spikes in summer by the water’s edge, full of bees and butterflies.
• Yellow flag: Yellow flowers in May–June at the foot of the willow, with its feet in the water.

Osier: when and how to plant it?

1. Plant from November to March as a bare-root plant, or simply push a fresh rod into the ground: it will root by itself.
2. For a living willow den or tunnel: in February–March push rods of 2–3 m about 30 cm into the ground, 20–30 cm apart, and weave the tops together.
3. Keep grass and weeds away from young plants so they are not smothered.
4. Water in dry spells during the first spring and summer.

Care

Watering

Not needed in a wet spot; on drier soil, in dry spells during the first year.

Feeding

Not needed.

Coppicing

Every one to three years in winter, for long, straight rods.

Willow den

Weave the new shoots into the framework during the year, and cut back whatever is too long in winter.

Tip: Use the rods from your osier to build a living willow den for the children: in February, push long rods into the ground in a circle and weave the tops together. After one summer you will have a green den.

Osier: when to prune it?

Pruning months: December–March.

When: While dormant in winter, from December to March.

How:

• Coppice or pollard it every one to three years, just above the ground or the pollard head: this gives long, straight rods.
• Use the rods fresh for weaving, or let them dry and soak them in water for a few days before use.
• If you would rather have a shrub than coppice, just remove a few old branches each year.

Caution: Don’t prune during the nesting season (mid-March to mid-August) if birds are nesting in the shrub.

Pruning: when and how · Pruning calendar and basic rules

Propagation

Hardwood cuttings

In winter, push 20–30 cm lengths of one-year-old shoots two-thirds into the ground; they almost always root.

Long rods

For a willow den or a living screen, push long rods straight into the ground in February–March.

Osier: how does it get through the winter?

Hardy throughout Belgium: no protection needed.

• Fully hardy.
• In winter, without leaves, the long rods are easiest to see: the time to coppice and harvest.

Diseases and pests

• Blue willow beetle: Small, metallic-blue beetles and their larvae make holes in the leaves or skeletonise them in summer. The shrub simply regrows the next year.
• Willow rust: Orange pustules on the underside of the leaves in late summer, and early leaf fall. Harmless for a shrub you coppice anyway; clear up the leaves.
• Roots in pipes: Willow roots get into leaking sewers and drains. Plant it well away from them.
• Drought: Leaf drop and weak growth in a spot that is too dry. Choose a moist spot or water.

Through the year

• January: Coppice and harvest the rods.
• February: Coppice; plant a living willow den or tunnel.
• March: Catkins for the bees; last pruning, before mid-March.
• April: Catkins; it comes into leaf.
• May: Fluffy seeds.
• July: Weave new shoots into the willow den; watch out for willow beetles.
• November: Planting and hardwood cuttings.
• December: Coppicing can start; rods for Christmas wreaths.

What can you use it for?

Also used for

Rods for weaving, baskets, mats and living willow dens or tunnels.

For wildlife

Early catkins for bees; food plant for many caterpillars.

Garden and landscape

Fast, moisture-loving shrub for beside a ditch or pond.

Good for wildlife

Bees

Nectar and pollen for honeybees and wild bees.

Caterpillars

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

Bumblebees

Nectar and pollen for bumblebees, also from deep flowers and early in spring.

Moths

Nectar for moths, often from flowers that are scented in the evening.

Birds

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

Did you know?

• The willow for weaving, baskets and living willow dens: the shoots grow up to 3 m in a single year.
• Willows have separate sexes: a plant bears either yellow male catkins or greenish female ones.
• Willow bark contains salicin, used for centuries against pain and fever, and the basis on which aspirin was later developed.
• The species name viminalis comes from the Latin vimen, ‘a pliable twig for weaving’. The Viminal, one of the seven hills of Rome, is also named after such osiers.
• In osier beds such as those of the Biesbosch in the Netherlands, willows like the osier were grown for brushwood, woven into fascine mattresses to strengthen dykes and banks.