In Nintendo's Super Mario Bros. game, the bushes are just clouds that have been colored green.

Mario was originally known as Jumpman. However, when Nintendo’s US office were trying to think of a better name in time for the American release of the game, they were interrupted by their landlord Mario Segale, after whom they christened the character.  Hardware graphic limitations...
In Nintendo's Super Mario Bros. game, the bushes are just clouds that have been colored green.