Based on some suggestions received on a previous photo (Sunflowers in Tuxedo). I left color on a few selected sunflowers and a firewheel. Let see, I selected, inverted selection and used channel mixer to convert to black and white. I remember the days when I use to have to stay locked up in my darkroom trying to do this. I don't miss the chemicals. In any case here is this variation.
I believe if you were still using the dark room Otto, you would have increased the contrast... anyway... if you like this direction, I suggest colorin only one flower, positioned in a very good spot in the photo, to lead my eye inside the frame.