Hex #559040 or rgb(85,144,64) in RGB space is the tint of grass green. It has hue angle of 104.25 degrees, value = 56 and saturation = 56. #559040 can be obtained by mixing 4 colors: 1 drop of yellow, 4 drops of green, 3 drops of white, 4 drops of black.
Nearest safe hex - #669933. Below you can see the block with #559040 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #559040 to the mixer and play with it.