Leaves are flat and one dimensional but the way they twist and turn makes the shadows within them which can be used to define their form. The ultramarine blue and new gamboge make nice yellow green to green mixes without having to dull them with a compliment. Schminke`s indigo (this is quite opaque) can be added to give the blue greens. A bit of ruby red added to the UB blue and yellow mixes gives some nice darks for shadows. Since these are small areas, they can be most conveniently done by the wet on dry method. Leave a fine line for the central vein in the first wash and gently blend it in with a yellow green in the next wash. It won`t look right if you u paint it in after the leaf has completely dried. While doing the individual leaves, the overall form of the plant has also to be kept in mind… the upper leaves catch the light, they have the most yellow in the yellow greens, the leaves at the bottom are in shadow and they are the darkest, a few leaves which are flat and without details will give the illusion of depth. In my reference, there`s very little interest in terms of the value arrangement and all the values lie almost exclusively in the mid range. By making the lights lighter and shadows darker, I`ve extended this range a little.
The lilac leaves right under the lilacs reflect a little of the flower color, so drop in a bit of the reds in the leaf washes. This adds interest to the leaves and ties the flowers and leaves together visually. The peony leaves actually do have a bit of the warm red in them at the edges. I`m going to make them a bit darker and cooler since here the peony bush is placed under the lilac tree. Always check whether the veins are opposite are alternate flowing, here they are alternate.