Hex #558b47 or rgb(85,139,71) in RGB space is the tint of grass green. It has hue angle of 107.65 degrees, value = 55 and saturation = 49. #558b47 can be obtained by mixing 4 colors: 4 drops of yellow, 5 drops of blue, 2 drops of green, 1 drop of black.
Nearest safe hex - #669933. Below you can see the block with #558b47 color and its structure: in procentage ratio and in drops of pigments. Click "TRY" button to move #558b47 to the mixer and play with it.