Hi Nick - I really like these
So far as suggestions, I have a couple which may or may not help
1. This, to me, is probably the weakest in this series. While I normally like a bit of grain (noise) in a picture like this, I think it is a little too apparant in this one - maybe it's just the texture and lighting, but it just looks too noisey for me

I think the harsh shadow on the right also adds to this impression - perhaps if that wasn't there, the colour and texture would work better (again, this is my opinion - I bet that others will have a totally opposite opinion

)
2. Wonderful

Love the lighting, love the DOF, although the little brown bit is a little distracting.
3. Consider cropping just above the third level and leaving (or is that leafing

) the fourth out. Again, lovely light
4. Really like the way the sharp edge is offset by the softer bottom leaf. Nice detail
