Salix fragilis

Crack willow or brittle willow is in the willow or Salicaceae family and is native to Europe and Western Asia, found along rivers and streams and in marshes. It grows up to 20 m in height. Crack or brittle in the name refers to the ease by which is is damaged by wind, frost and snow.

Some botanists suggest that S. fragilis is a hybrid between several other species of willow, but this is not supported rigorously by evidence.

It has been introduced ornamentally into various parts of the world and now often is an invasive species, being found extensively in the upper half of the United States and in Canada.

• Leaves are simple, alternate, lanceolate, 9–15 cm long and 1.3–3.0 cm across with finely serrated margins.
• Species is dioecious, with male and female catkins on separate trees, both being 4–6 cm long. Seed capsules burst and release cotton-tufted seeds in late spring which are easily distributed in the wind.
• The tree is often multi-trunked and irregularly shaped, with gray-brown fissured bark in older trees.