tree Common Osier (Salix viminalis). The Common Osier is a species of Willow. It is a large, fast-growing waterside shrub with an upright growth habit reaching between 3-6m (rarely up to 10m).

leafThe Osier has long, slender leaves with untoothed margins that open following the appearance of catkins in the spring.
catkins The flowers are dioecious, with male and female catkins on separate plants. The male catkins are yellow and oval-shaped; the female catkins are longer and more cylindrical. They mature in early summer when the fruit capsules split open to release the numerous minute seeds. seeds

Along with other related willows, the flexible twigs (called "withies") are commonly used in basketry, giving rise to its alternative common name of "basket willow".