Hex #559d39 or rgb(85,157,57) in RGB space is the tint of grass green. It has hue angle of 103.20 degrees, value = 62 and saturation = 64. #559d39 can be obtained by mixing 4 colors: 1 drop of red, 5 drops of green, 2 drops of white, 1 drop of black.
Nearest safe hex - #669933. Below you can see the block with #559d39 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #559d39 to the mixer and play with it.