I love this flower so will be teaching this project at Anne Arundel Community College this week. Here is a step by step description of how it is done. Notice the yellow leads the viewer in diagonally across the picture.
This is the first step. I painted the background wet on wet with three primary colors. I used Permanent Yellow, Permanent Rose, and Cobalt Blue. I left the paper dry around the flowers.
This is the first step. I painted the background wet on wet with three primary colors. I used Permanent Yellow, Permanent Rose, and Cobalt Blue. I left the paper dry around the flowers. 

I love this type of design with a central window. The colors are limited which is the very best way to go. I am playing with two opposite colors - blue and orange. Notice the negative painting outside the window in the border area. This negative painting technique creates the mystery.



