For me drying of leaves is not a spontaneous process, because when we  say spontaneous there should be no input of energy it should occur on its own but for the drying of leaves this happens due to the heat from the sun so there is input of energy that makes it a non-spontaneous process
yes it is an spontaneous process because dry leaves and falling happens naturally without human control and manipulations..........
when we say input of energy it does not mean energy exerted by human beings, our environment also exerts energy on things