From M:TG Archive, a library of Magic: The Gathering information

Green is the color of life, nature, growth, instinct, and interdependence. Typical green creatures include natural animals, elves, and druids. Green has the best creatures, of all sizes, among all colors; it is excellent at being able to bring more lands in play and generate more mana; it is the best color for destroying artifacts and enchantments; and it has many ways of gaining life. However, green has difficulty removing opposing creatures from play, and has almost no strategies that are not creature-based.