Here I've done my first background layer, after having covered my flowers and leaves with soy wax to preserve them. I just laid down wet washes of color in a pretty haphazard way. I decided on a sort of dual complementary color scheme, with violets and red-violets setting off the yellows and yellow greens.
After the background was dry, I waxed in (painted on hot wax with a paintbrush) some leaf shapes in the lower left and under the central leaves, and added some swirls. The wax darkens the silk, so right now it looks like I've painted extra leaves with dye, but that's actually the wax. When the wax is removed, the lighter colors underneath will reappear. The next step is to paint a second background layer; the areas I've just waxed in will be preserved.