绿树成荫: the trees make a pleasant shade.; trees shade the street
绿叶成荫: grow branches and scatter leaves -- a woman who has many progenies; the thick foliage forms a good shade -- she has become a mother of many children.; a young mother of many children
插柳成荫: plant a willow slip hoping to enjoy the shade of the tree; do sth. which brings results without effort [easily]; work for the benefit of future generations; work for the future rather than
