The phrase "green grass" refers to the color of a type of plant, specifically the vibrant, natural shade of the grass when it is healthy and well-watered. Full definition
If I lived here I would have so much fun watching my kids and dog play on that patch of green grass. (theinspiredroom.net)
He noted that these nutrients were most plentiful in the spring and fall, when cows had access to rapidly growing green grass. (westonaprice.org)
They're located on a 20,000 - square - metre beachfront property covered with green grass, palm trees, fruit trees, horses, friendly dogs and a fun wave right out front. (flightnetwork.com)