I really like your composition, Joanna, but I think you use some more sharpness on the stem and leaf. I see you made the image at 1/10th - was that handheld? If so, I'd recommend getting out the tripod or raising your aperture (not that you don't know that!)
Nice subject. IMHO, the bright stem (especially the upper part) is a bit bothersome - perhaps cud be toned down a bit...?
(Am not sure if its my monitor!!!)
Might agree with Julie on sharpening.
TFS Joanna.
You really should try using flash with macro, for fill not full blast auto. I dont even try to shoot macro without it. It gives you consistently sharp images and soft lighting.