Good strong composition with just the monarch and the single flower, all on a slight diagonal, and the beautifully blurred bkgd of greens. And I do like that bit of orange in the bkgd, just beyond the butterfly. It visually continues the diagonal of the main objects. On my monitor those red-oranges of the petals appear overly saturated, completely overwhelming the butterfly.
Very nice Stuart. That is a Queen butterfly though, not a Monarch. I like the composition for the reasons Nancy stated. The Mexican sunflowers are VERY orange, so you tend to have to desaturate them a bit in photos. Overall, I like it. :)