I was unable to find any shamrock or four-leafed clover to photograph, but the lush, damp woodland floor shows the verdant nature of this colour anyway. It is the colour of vegetation, growth and renewal of life, and is said by some to be the colour best focused on the retina, so maybe that is why it is found to be so restful to the eyes.
Green is the essence of harmony and balance, and is used much in healing, indeed in olden times crushed emeralds were used – presumably just for the rich! It is associated with the heart chakra and symbolically also relates to hope, fertility, new life, resurrection, abundance, and youthfulness.