Hex #559f39 or rgb(85,159,57) in RGB space is the tint of grass green. It has hue angle of 103.53 degrees, value = 62 and saturation = 64. #559f39 can be obtained by mixing 4 colors: 1 drop of yellow, 2 drops of red, 2 drops of cyan, 4 drops of green.
Nearest safe hex - #669933. Below you can see the block with #559f39 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #559f39 to the mixer and play with it.