i really like the composition here, and the simplicity of the image. the muted colours of the background provide a pleasing foil to the flower head, and there is just the right amount of separation between the two.
The background is not uniform enough for my tastes -- I think something in the background that adds more contrast to the petals would have worked well -- a darker colour. I find the red/pink hues in the background distracting and they are drawing my eyes away from your focal point.