That is how weeping willow got its name. Willow trees have elongated leaves that are green on the upper side and whitish on the bottom side. Color of the leaves changes seasonally. Leaves turn from green to yellow in the autumn. Willow is deciduous plant, which means that it sheds its leaves each winter.Willow has extremely strong and well developed root.ompound isolated from the bark, called salicin is used in the production of very popular and widely used drug: aspirin. This is just one of numerous beneficial compounds that can be found in the willow. People chewed bark of the willow tree to treat fever, inflammation and pain in the past.