I found this at the link below:

"Color, like the actual scenes and pictures, also came to play a symbolic and powerful role in communicating Navaho tradition. The colors often portrayed inexplicable emotion that only the Navaho could comprehend. Green stood for youth, and represented nature and the power and energy that nature brought. It was the hue of promise, hope, growth, and life to come in the crops of the future. Yellow, orange, and blue represented maturity and more specifically, harvest time. This was a positive time for the Navaho, bringing them peace, happiness, and power. Commonly, the colors of brown and gray became popular in the weaving following a failure in the harvest, for these colors represented death and decay. White, in contrast, was viewed as a symbol of innocence and purity, often representing the first hours of a newborn plant or animal. Lastly, the most powerful color in the eyes of the Navaho is red. The NavahoÂs love for red, according to James, was "Not a mere vagary, a whim, a fancy of the eye, barbaric taste n the wildly gorgeous, a flaunting of his inability to appreciate color, but a keen and grateful recognition of one of the greatest gifts of the gods to menÂ"(p. 61). This "gift" that James is referring to is the sun. The sun was the Navaho way of life. It brought exhilaration, joy, and daily stimulation to the Navaho man. Colors, like the pictures, were a means of communication throughout many Navaho textiles. The difference however, is that they were more a means of keeping tradition alive in that only the Navaho would truly understand the significance and symbolism behind each one."

Hopefully this will help you choose,
Wendy

Here is a link that might be useful: U. of Arizona paper

Since he likes blue, and she likes green, why not combine them? Splash in a little orange for contrast and set it all off with a soft pale cream. Should be stunning...
Just my 2c...
Sharon

Use the blue maybe in 2 different shades, then add 2 different shades of green and now one each of white and black and alternate....White and the Black will bring it all together in a wonderful way....try a small swatch.