I find the unfocused stamen in the foreground to be distracting, but overall it is a good photo and certainly meets the challenge. If it was your intention to use a shallow depth of field, I think I might have kept the stamen in focus and allowed the petals to be blurred.
I hesitate to make comments since I am obviously not an expert, but here goes: I do like the composition of this shot but felt a better focus was needed.
You had a super idea here. Maybe your exposure is a little off, but your composition is excellent. Try using a tripod or some other support for your camera on these closeups, as you have a good eye for this type of image.
very nice subject matter and use of color & framing, but focus leaves image uninteresting. If you are using the petals as the subject matter, take the center stems out of the way, set them on the side of the image so we can see more closely the detail.