I really like the last one!! It's kinda a flower abstract.
Just something to think about as you continue to play around w/ flowers. What type of shot are you going for? Are you looking to document a flower or create art?
I guess I'm a little bit more into the artistic direction as I often tend to like pictures I find have a more "artistic" feel to them rather than purely photographic perfection.
I like the colors and exposure in the first one, but not the composition. It looks like it just accidentally didn't all get in the frame, rather than anything purposeful. I tend to treat my flower shots like portraits in the sense that, if I'm going to crop off parts, I'm going to make it obvious that I *meant* to crop them, rather than just leaving the edges cut off, like I just didn't quite leave enough room. Not sure if that makes sense--a lot of the stuff in my head doesn't.
Also, I agree with mishele that the last one is a kinda cool abstract, but--if it were mine--I think I'd try to play that abstract aspect up by cropping both sides to get rid of the black/dark green background, and a little off the bottom for the same purpose--crop JuST above where the background shows, so all you're left with is the petals. That's just MY take on it.