Hex #559739 or rgb(85,151,57) in RGB space is the tint of grass green. It has hue angle of 102.13 degrees, value = 59 and saturation = 62. #559739 can be obtained by mixing 4 colors: 5 drops of yellow, 5 drops of blue, 4 drops of green, 1 drop of black.
Nearest safe hex - #669933. Below you can see the block with #559739 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #559739 to the mixer and play with it.