Hex #559b39 or rgb(85,155,57) in RGB space is the tint of grass green. It has hue angle of 102.86 degrees, value = 61 and saturation = 63. #559b39 can be obtained by mixing 4 colors: 2 drops of red, 1 drop of cyan, 5 drops of green, 1 drop of white.
Nearest safe hex - #669933. Below you can see the block with #559b39 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #559b39 to the mixer and play with it.