That is not to say it is impossible. Medium green is a great color to venture into when you realize that 80% of your shirts are either white or blue. Most guys who can wear blue well, can get away with green. The only ones I would steer away from that hue are those with very pale coloring. Green against pale skin makes one look sickly - and we don't want that.
Here is my lovely assistant Gerry, totally rocking the green. Please notice - the suit is not black. I encourage both men and women to stay away from black, when combining with other colors. It is much too harsh and often takes all the life and dimension out of interesting hues. In this case we have a very dark charcoal gray pinstripe suit, further livened up by a bit of texture in the fabric. Such details may seem insignificant, as they are small and barely visible, but trust me - they do contribute to the overall effect.
The shirt is a very nice grayish-green color (also known as "loden") and, as you can see, creates a look that is perfectly dressy yet not at all stodgy. So much so, that wearing the outfit without the jacket still works.
One of my favorite elements of this look, however, is the tie. We bought it only recently (I think we found it at Belk's), and it has rapidly become Gerry's favorite. It can be easily worn with green, rusty brown, gray, black or white. Depending on which color shirt you wear, it brings out that particular color in the tie, which pulls the whole look together.
In general, when it comes to ties, I would recommend investing in a few high-quality ones than a whole bunch of cheap ones. So, if you are on a budget, make a point of finding ties like the one shown here, that you can wear with many different things.