The willow
The Wood Guide · The forests
Tree portraitThe willow
Characteristic drooping branches, unstoppable vigour and a love of water. And a substance in its bark that changed medicine.
- Salix spp.
- 2 to 3 metres a year
- Salicin → aspirin
The willow at a glance
One of the most picturesque trees in our landscape, and at the same time one of the most useful — ecologically, for crafts and medically.
The willow grows exceptionally fast: two to three metres a year is normal, and it reaches fifteen to twenty-five metres. Its extensive root system makes it a natural water manager: it reinforces banks, holds soil together and absorbs large quantities of water.
And it is almost impossible to kill. A broken-off branch that lands in damp soil takes root and becomes a new tree. That is exactly why it grows everywhere along ditches and streams — often without anyone having planted it there.
Willow bark contains salicin, which the body converts into salicylic acid. As far back as antiquity people chewed willow bark against pain and fever. In the nineteenth century chemists isolated the active substance and turned it into acetylsalicylic acid — aspirin. The name Salix still lives on in the word salicylic.
- Botanical
- Salix spp.
- Lifespan
- 50 to 100 years
- Height
- 15 to 25 metres
- Growth rate
- very fast: 2 to 3 m a year
- Leaves
- long and narrow
- Branches
- flexible, often drooping
To be fair: that vigour is also the problem. Willow roots seek water and invade sewers, drains and septic tanks; the branches break easily in storms; and a willow too close to a house is a tree you will be busy pruning within ten years. Plant it with plenty of space, or don't plant it.
Two to three metres a year
The willow grows two to three metres a year and reaches fifteen to twenty-five metres. Its extensive root system reinforces banks, holds soil together and absorbs large quantities of water.
Click a chapter or use the arrows · growth and roots schematic.
Features at a glance
| Characteristic | Description |
|---|---|
| Lifespan | 50 to 100 years |
| Height | 15 to 25 metres |
| Growth rate | Very fast — 2 to 3 metres a year |
| Leaves | Long and narrow, often silvery underneath |
| Bark | Deeply furrowed on older trees |
| Branches | Flexible, drooping in many species |
| Flowering | Soft catkins, very early in spring |
Willow catkins flower before almost anything else, sometimes as early as February. For bees and bumblebees just emerging from winter they are one of the first sources of pollen and nectar — a reason to leave willows standing along field margins.
Why pollard willows exist
The pollard willow is not a tree species but a form of management. By cutting back the crown completely every few years, you force the tree to produce new, straight shoots each time — and for centuries those shoots were a raw material.
Wickerwork
Straight one-year-old willow withies are flexible and strong: baskets, fish traps, fences and even the walls of half-timbered houses.
Binding material
Before string existed, people tied things with willow withies — in viticulture, fruit growing and thatching.
Firewood
Regrows quickly and is therefore a renewable source close to home, even though willow burns only moderately.
Landscape
Rows of pollard willows are typical of the Flemish and Dutch landscape. Without maintenance they eventually split open under their own weight.
A pollard willow that is no longer cut keeps growing until the heavy branches split the hollow trunk apart. If you have an old pollard willow in your garden, you need to cut it back every three to six years — precisely to keep it alive.
What the willow yields
Light and soft
One of the lightest native hardwoods, soft and fibrous. It does not splinter easily, which makes it suitable for tool parts and toys.
Cricket bats
The best-known use worldwide: Salix alba var. caerulea supplies the wood for cricket bats, for its combination of lightness and shock resistance.
Wickerwork
Not the wood but the one-year-old withies — flexible, strong and harvestable every year.
Not durable
Above ground, willow wood lasts only a few years. It is not an option for garden furniture or construction.
Because fresh willow branches take root in damp soil, you can build things with willow that keep growing: living tunnels, huts and screens. Push the branches thirty centimetres deep into moist soil in spring and they will sprout by themselves.
Frequently asked questions about the willow
How fast does a willow grow?
Two to three metres a year is normal. That makes it one of the fastest-growing trees in our region — and so also a tree to plant well away from buildings and pipes.
Is it true that aspirin comes from willow bark?
Originally, yes. Willow bark contains salicin, which the body converts into salicylic acid. Chemists isolated it in the nineteenth century and turned it into acetylsalicylic acid — aspirin.
Why are willows pollarded?
To keep harvesting new straight shoots for wickerwork and binding, and to stop the heavy crown splitting the hollow trunk apart. A pollard willow needs cutting back every three to six years.
Can willow wood be used outdoors?
Hardly. It is soft and not durable. For outdoor work you look at oak, robinia or pressure-treated wood.
The willow in perspective
It bends but doesn't break — and grows back where it did break.
Have a question about your project? Just ask — we're happy to help.