I agree with Bob, the background is a little too hot/bright and detracts from the beauty and simplicity of the petunias. Also, the front petunia petals don't seem to have quite enough contrast as the top of the petunia blends into the background. I like the colors and the composition, with the exception of the petunia in the right bottom.
Nice but I would try working with levels to bring the purple in flow out more. Did you move the trianlges into the histogram. It just needs more pop on saturation and contrast for me.