When you don't have fresh flowers, use silk!

I needed a quick "model" for a demo in my Tuesday watercolor class in Kettering, so I grabbed my digital camera and shot a dozen macro pictures of silk flowers I had on hand. I liked this shot the best. I didn't take a lot of pains with the drawing (obviously) because my students were primarily interested in figuring out how to make petals look 3D and how to not get "lost" in all those petals. Still, I think the resulting painting came out pretty well...

For any students out there, this was a limited palette painting. I used quinacridone red and permanent alizarin crimson (both pigment PV19) for the petals. The background is a mixture of quinacridone red and pthalo green just slopped on very loosely. Background petals were "desaturated" with just a TINY bit of pthalo green. There is a little bit of negative painting here and there at the bottom. The yellow center was added with Naples yellow and American Journey Sour Lemon.
If you have trouble keeping the color of your flower petals bright and clean, try to avoid mixing two or more different pigments together. It's very easy to unintentionally include a neutralizer in the mix. For example, if I'd mixed a red-orange with alizarin crimson, the slight blue cast in the alizarin would have dulled the red-orange a bit, and vice versa (blue and orange are opposites on the color wheel and neutralize each other).
Now, if I really wanted to make this daisy a bit more orange, the way to do it would be to paint an underpainting of yellow, dry it completely, and then paint red over it. The yellow glows through the red, and the result is gorgeous. (Yes, this means you have to think ahead. LOL)