This picture goes back 5 or 6 years, and is one of my earliest examples of "the wash method." The whole background piece...the north wall of our studio...was in shadow, and the whole foreground was in full sunlight. It was a natural for the indirect, wash-over-wash method. I simply decided that the lightest value in the background piece was that gray-green of the batten strips, then ran a wash of that color over the entire piece, saving the foreground bushes (and a sliver on the windowsill) as white paper. Working this way handed me two big advantages: it ensured that the background piece would have "unity," as nothing in the background would be lighter or more intense than that gray-green. And it simplified the actual painting process...with the color and value of the battens already on the paper, to "make" them I simply had to paint the dark green siding between.
Once the background was finished, I painted the rhododendrons in the foreground in "line and stroke," using the same red/green/blue combination as in the background, but at much higher intensities. "Studio Window," watercolor on Arches paper, 11" X 15."