Side by side
White willow or crack willow? How to tell them apart
Salix alba · Salix × fragilis
You can tell a white willow by its narrow leaves, silvery and silky on both sides, which make the tree look silver-grey from afar; a crack willow has longer, glossy green, almost hairless leaves and twigs that snap off at the base with a crack.
Look at the colour of the crown: silver-grey on the white willow, glossy green on the crack willow. Bend a twig sideways: on the crack willow it snaps off at the base with a sharp crack, on the white willow it bends much further.
| White willow | Crack willow | |
|---|---|---|
| Leaves | Alternate, lance-shaped, 5–10 cm, finely toothed; both sides (especially the underside) silky and silvery-hairy. | Alternate, 7–15 cm, lance-shaped with a long pointed tip, coarsely and somewhat irregularly toothed; glossy green above, blue-green and (almost) hairless below. |
| Flowering | Catkins in April; male and female on separate trees (April). | Slender catkins in April, together with the leaves; male and female on separate trees (April). |
| Fruit | Fluffy seeds in May–June. | Fluffy seeds in May–June. |
| Bark | Grey and deeply furrowed in a network pattern. | Grey and deeply furrowed in a network pattern. The glossy, yellowish-brown twigs break off easily at the base. |
| Shape and height | Broadleaf tree, 15–25 m, often pollarded | Broadleaf tree, 10–20 m, often pollarded |
| Site | Full sun, any garden soil, moist to wet | Full sun, any garden soil, moist to wet |
| Native to Belgium | Yes | Yes, long naturalised |
| Good for bees, butterflies and birds | Yes, for bees, butterflies and birds | – |
| Poisonous to people and pets | Not known to be poisonous | Not known to be poisonous |
| Pruning months | November–March | November–March |
The best feature in each season
- Spring
- Both flower in April with catkins, together with the leaves, with male and female catkins on separate trees. The young leaves of the white willow are silvery and silky straight away.
- Summer
- The leaf decides it: on the white willow 5–10 cm, finely toothed and silky; on the crack willow 7–15 cm, coarsely and irregularly toothed, glossy green above and bluish green below.
- Autumn
- The white willow stays silver-grey until the leaves fall, the crack willow turns yellow. Snapped-off twigs of the crack willow often lie under the tree.
- Winter
- The glossy, yellowish-brown twigs of the crack willow break off easily at the base; those of the white willow are thinner and tougher. The bark of both is grey with a deep network of furrows.
Where do they grow?
Both line streams, ditches, rivers and wet meadows, mostly as pollards. The white willow is native; the crack willow is an old hybrid that has grown here for centuries. Many willows along the water are hybrids with intermediate forms.
Which one for your garden?
- As free-standing trees they grow to 10–25 m with a broad crown: nothing for an ordinary garden. As pollards by a ditch, a pond or in a meadow, both are superb for wildlife: hollows for little owls and bats, catkins for bees in April.
- For a pollard, prefer the white willow: the branches of an unpruned crack willow split off easily. Do not plant them close to the house or drains, as their roots seek out water.
Did you know? A snapped-off crack willow twig floats downstream and takes root wherever it washes up: that is how it spreads along rivers, without seed.
Read on
- Plant profile: White willow
- Plant profile: Crack willow
- White willow: when and how to prune
- Crack willow: when and how to prune
- Identification key
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