The willow catkin, or pussy willow, is a familiar feature of the spring landscape in shrubby areas. Some willows flower before the leaves open out, while in other species the leaves appear first. The willows vary from prostrate or creeping dwarf shrubs to erect bushes or small trees, usually with many stems. The short-stalked leaves are long and narrow with smooth or finely toothed edges.
 
Willow bark contains a chemical called salicin, which is similar to aspirin. It has pain and fever reducing effects in the body.
People commonly use willow bark for back pain, osteoarthritis, fever, flu, muscle pain, and many other conditions