Direct experiment with kanji “blue, green”
When I studied the kanji ‘blue’ I was surprised to see it also means ‘green’. I thought how crude this language is that there’s only one kanji for 2 different words. Grudgingly accepting this unlogical kanji made using it awkward and grudging. One morning when I went out to jog, I was standing near a high bushy tree with green leaves. The sky was blue, clear. Then suddenly a breeze made the branches and leaves wave before my eyes. At this moment green leaves waving to left and right with blue sky background created a mix of color which was neither pure blue or green. I could not tell it was blue or green. Perfectly 2 colors were at the same time at this angle. Just experiment it. So, this kanji has no problem of being wrong.
kanji “blue, green”. Its components are:
life, growth, new shoot of plant springing up from ground 
(this was the bush with green leaves, in my case) and
moon
which is still in the sky in the morning in many cases. The fact that moon is visible means the sky is cloudless, clear.