A calibrator can push the reds and blues to even the green push out, if that's the case on your specific set. If it's not something you're able to do, you might consider a professional calibration.
Also, on occasion, C|Net's Picture Settings Forum may have some tips. You can check that out here:
I need help calibrating my Samsung unb8500 to achieve the most accurate primary colors. I have the TV set to standard and have tried minor tweaks with a calibration DVD but I cannot get the green to be perfect. In some shots the green(such as grass) seems too contrasty and neony. The green seems to be the only color that is off and I want to achieve the most realistic green. The only thing that helped was to adjust the color space to auto which did make the green natural but it seemed to mute the overall colors.
I like the way the picture looks set to standard with the color space set to native, but the green does not seem correct in some shades of the color. Please help.