I'd like to see this cropped closer to the flower; there's a petal-less flower right behind it, so the one on the left isn't really necessary. Also the bottom of the flower is a bit OOF, as opposed to the top half of it, which could have been hidden with cropping the picture closer.
Great background! I love the colors too! I don't know if i'm right, but there is a part without focus at the lower part of the sun flower? Still a great photo...In my opinion this is one of the bests flower picture in this challenge.