Look at the edges of the leaves; they get cooler and change of color. The purpose of that is to attract the eyes towards the warm regions in the middle of the painting. The big leif at the left has more yellow in the middle to create volume and contrast with the violet flowers. The leaf below at the bottom left is cooler and darker to give importance to the one on top of her near the flowers.

Don't forget the light comes from the right.
Look at the shadows near the heart of the flowers; it is more precise, darker and cooler. As it comes closer to the end of the petal where the light strikes, it gets lighter.

Look at the shadows of the flowers on the foliage. At the right and top-right, they are warmer and at the right; away from the sun and behind the flowers, the shadows are darker and cooler.
These subtil changes of warmth are sometimes forgotten by the untrained eye, but the artist as to be able to transfer those details to create visual impact in the painting.