Here's the step by step process from start to finish. I had a nice bouquet of lovely sunflowers in my office from which to draw inspiration.
I rearranged the flower on the left in my drawing below to create a better composition.
The smaller sketch below the drawing on wc paper is my value study - making sure to have lights and darks in a pleasing arrangement for balance and harmony, but not to be boring!
Adding the first washes of watercolor - sunshine yellows!
Adding the first washes of greens in the lighter values.
Adding the dark center to create contrast.
Adding the background contrasting color so help the sunflowers pop off the page. And the final painting, after adding some darker darks to the flower petals to create a better sense of depth. Plus a signature!