I remember when I first started painting, I told someone that I really did not like painting trees and rocks. The response was "you live in Maine! You are in big trouble!"
Almost every green pigment that you purchase or any green mixture that you make yourself will require a tiny bit of red or rose in order to make it look natural. Just try it.
Greens found in the landscape are often more "neutral" than they are painted.
Here's a suggestion: set aside an hour three times a week. Mix each of your blues with one yellow (i.e. use cobalt, ultramarine, cerulean, phtyalo and aureolin yellow). Make a 3" square. Label each one. Then, change the yellow (i.e. cadmium yellow) and then continue through each of your yellows, and using the same blues, mix new greens. Be sure to lable each one.
Next, try each of these mixtures with a touch of one of your reds and see what results.
You can also take each of your tube greens and modifiy each with a bit of your reds or roses in the same way. Adding a little rose madder will give you a very different result than using cadmium red or alizarin crimson.
If you label each mixture, you will have quite a library of greens to use in your next painting.
This sounds like a lot of work, but I can promise you that it really doesn't take that long!
This plein air painting was done over a period of four mornings as the light and shadows changed by 9:30 am.
Notice the variety of warm and cool greens in this painting
Let's Begin with the Greens that are Far Away
We know that cooler colors will stay back while warm colors come forward.
(there are exceptions to everything, but as a general rule, this works).
So in order to set the stage, I mixed some cool greens using aureolin yellow and cerulean blue, as well as viridian plus a bit of aureolin and a wee touch of permanent rose and cobalt blue. By varying the amount of yellow and red you can get several varieties of green. Just remember to keep them "cool" so don't add too much yellow.
The sky began with cobalt blue graded to cooler cerulean and then to naples yellow behind the trees.
Look at the pale cool greens that were painted into a sky wash that was still damp.
I think you can see the progression of cool to warmer greens as the trees came from far away to nearer to my line of vision.
The sun-lit grass area by the gate was very bright and was painted as a warm yellow-green. Varying amounts of green and blue were added as I painted into the shadowed areas.
The dark cyprus trees also included some warm and cool variations. Always observe the angle of light; it will help create the dimensional form of the tree.
We have barely scratched the surface of all the ideas and ways to make greens a beautiful part of our paintings. But progress begins with small steps and I know that just having a "vocabulary" of three warm and three cool greens as well as some complimentary shadow colors will make a world of difference in your paintings.