I painted the background by moistening where I wanted the paint and using fresh pigment on my brush. Winsor Green (Yellow) and Cadmium Yellow. Make sure your paint brush is just damp so that when you apply the paint it will diffuse softly and give you soft edges. You don't have to always rinse your brush out before dipping into green or yellow.
The flowers were painted with ultramarine blue and the grayish areas in my photo are actually new gamboge added at the end of the ultramarine wash to just neutralize the blue a bit and give a glow near the edges. Paint each flower petal separately so you have some control You've got to pull the washes quickly and use enough pigment and water. Start near the center where the color is darker blue and draw it out to a lighter value towards the edge, adding pale new gamboge. (Try not to keep going over areas and stroking your paint on like you might with oils or acrylic, this will just stir it up and make a mess.) Remember, the wash will dry a couple of shades lighter and if your puddle of color isn't juicy enough and your brush isn't full of paint before you start the wash, especially with ultramarine blue, it will start to dry and you will get a "bloom". If you do, leave it alone. It's better to make it look like you did it on purpose. You might be able to lessen it with a second wash after the first one is dry. The flower centers are cadmium yellow.
The flower pot is painted with cobalt blue and touches of new gamboge. It looks kind of gray on my monitor but it's actually a dull greenish neutral.
I finished by wetting the petals and charging in some darker blue near the flower centers then while it's still wet (or you can wait for it to dry and rewet), I used a damp rigger brush and fresh ultramarine blue to paint in the streaks in the middle as well as a few dark nooks and crannies.