Hex #558f47 or rgb(85,143,71) in RGB space is the tint of grass green. It has hue angle of 108.33 degrees, value = 56 and saturation = 50. #558f47 can be obtained by mixing 4 colors: 3 drops of yellow, 1 drop of magenta, 4 drops of blue, 4 drops of green.
Nearest safe hex - #669933. Below you can see the block with #558f47 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #558f47 to the mixer and play with it.