Hanging gardens were a type of gardens.
Hanging Gardens of Babylon were one of the Seven Wonders of the World, originating from Babylon on Earth. (COMIC: Minus Seven Wonders)
Hanging Gardens of Slarvia were originally grown on rocks hanging in the air on Slarvia. (COMIC: Hacked)
Among other types, the Gardeners tended for hanging gardens on Tellus IV. (PROSE: The Secret in Vault 13)