Very, very stylish Andrew, I like this shot a lot and agree with Russ that it works perfectly well as it is and does not need any cropping, as there is just enough detail in the top darker area, to keep the image both balanced and interesting.
However being the OC control freak that I am, I would be tempted to do something with the blown out white area middle right, where what appears to be an un-diffused beam of light, is hitting the scene a little too harshly. I would perhaps try re-running the original raw file back through the raw converter and try to claw back a little bit of the detail into that area if at all possible, then overlay that as a new layer and then blend it back into the shot as a masked luminosity layer, yet without radically changing this shot - not a reworking of the shot, but a slight reworking of the blown out part of the middle right of the shot.
My other very slight and overly critical observations, means that I would also be tempted to clone out the very small darkish halo (is it a shadow?) around the top of the topmost petal and the main focus of interest and a couple of the smaller petals to the right. But all this nitpicking aside (and it is nitpicking I will totally admit to that), I think this is a really stylish piece of work, it is well conceived, well processed (other the above caveats of course) and well presented.
So not quite a bravo from me, but with a couple of minor tweaks, then it certainly would be.
Dave