Hi guys, thanks for the feedback, its all welcome :)
Rozumny and Yagi - My leaf materials are pretty simple. Diffuse and Translucency with glossiness and bump maps also. I have included an image showing the basic setup (bump was cropped off but it is set to .2) I have also included a couple of the reference images I started with. All the plants in this scene are built with vairations of this set up (maps/translucency/glossiness values change for each plant.
Polymax, thanks for the reply. Was there a specific material you are referring to?