Willow, crack (Salix fragilis)
Crack willow is a deciduous broadleaf tree and one of Britain's largest native willows.
Common name: crack willow
Scientific name: Salix fragilis
UK provenance: native
Interesting fact: the crack willow is named after the sound made when its branches and twigs fall, which they often do. Because the trees often grow beside rivers, any twigs that break off are carried downstream. This helps the trees propagate themselves, as the branches take root easily and may end up some distance away from where they fell.
What does crack willow look like?
Overview: the crack willow is hard to tell apart from the white willow. Mature trees grow to 25m. The bark is dark brown and develops deep fissures with age, and twigs are slender, flexible, shiny and yellow-brown.
Leaves: the slender leaves are similar to those of the white willow, being elongated (known as lanceolate), dark green above and light green below. However the leaves of the crack willow are shorter than those of the white willow, and they do not have a felty covering of fine, silky white hairs on the underside.
Flowers: the crack willow is dioecious, meaning male and female flowers are found on separate trees, in May. The male catkins are yellow, while the female catkins are green.
Fruits: once pollinated by bees, the female catkins transform into woolly white seeds, which are dispersed by wind.
Look out for: at maturity leaves are hairless and shiny on top and sparsely hairy below. Catkins appear before the leaves.
Could be confused with: other willow species which all freely hybridise. Crack willow often hybridises with white willow (Salix alba).
Identified in winter by: the twigs are brittle and make a 'crack' sound when snapped. Yellow-brown hairless narrow buds are pressed close to the twig.
Where to find crack willow
Distributed in the UK, Europe and Western Asia it is often found growing alongside rivers, lakes and watercourses. Crack willow is regularly planted to stabilise banks and dykes.
Value to wildlife
Caterpillars of a number of moth species feed on the foliage, including the puss moth, eyed hawk-moth and red underwing. The catkins provide an important source of early nectar and pollen for bees and other insects, and the branches make good nesting and roosting sites for birds.
Mythology and symbolism
All willows were seen as trees of celebration in biblical times, but this changed over time and today willows are more associated with sadness and mourning. Willow is often referred to in poetry in this way, and is depicted as such in Shakespeare's Hamlet, with Ophelia drowning near a willow tree. In northern areas, willow branches are used instead of palm branches to celebrate Palm Sunday.
How we use crack willow
Willows are prized for their slender, flexible stems, which have been used for many years to weave baskets and 'cribs' for animal food. Larger stems were traditionally used to make small sailing boats. A hybrid of the white willow and crack willow is the cricket bat willow, which is used to make cricket bats.
Crack willow may be susceptible to watermark disease.