First, we used construction paper crayons and colored pencils to make stems on black cardstock (5 1/2" X 8"). Children were asked to start at the BOTTOM of their paper (where a plant would actually start growing) and make stems of varying lengths and thicknesses. I also encouraged them to overlap stems and give them different directions to create the impression of movement.
Next, having viewed slides of wildflowers and noticing how they look sort of like blobs of color when seen from a distance, students used Q-tips to apply different colors of paint. Children had noticed how some flowers on the hillsides are clumped with like colors together, and on other hills the colors were pretty random. Their art reflected these different approaches. I only had 2 colors of paint at a table at one time, and then changed the colors, to encourage more thoughtful placement of "flower" colors.
The classroom teacher and I were both pleased with the balance of color that children achieved. As a side note, using Q-tips instead of brushes made for VERY easy clean-up. We even had time for a story after we put the paintings on the drying racks -- and that hardly ever happens!!