I have always taken the position that if it matches in nature, then it will match with artificial/man-made items. Since there is so much green in nature, green goes with everything.
my one and only balenciaga bag is green (sapin) and i love it! i would consider it a neutral since it matches almost anything. i actually bought it as a casual bag for my t-shirt/jeans days. it can't really be dressed up but that's because of the style, not the colour.