Complex leaf simulation, advice?

Hi, this is my first post here so I hope I have put this in the right place. I am in need of some advice. I need to create decaying leaves that fall off of a tree branch i.e. the leaf turns from green to brown, shrivels up and then falls off of the branch. All in the space of just a few seconds. Besides having a leaf model I’m not entirely sure on where to begin with this, any advice you could give me would be incredibly helpful. Thanks.