Tree Leafs to look like The Witness?

Hey all, Just have a simple yet confusing to me question, I have looked around the web for an example of how to do it and tried many different things. However none to look similar. So to start things off; My vertex Normals of my tree leafs are correct and are facing outward (sphere). The problem seems to be the transparent and Subsurface Scattering. If you can give me an example of how to fix through screen shots or link me to a post that will answer this please do!

Thanks in advance.