This song is about a breakup, and she's basically saying that even though it's over she'll never stop loving him. She sas "I'll move on when the the desert floods and the grass turns blue" The desert flooding and the grass turning blue are two things that are more then likely never gonna happen - therefore she'll never move on. And then she goes on to say "Someday when I stop loving you" basically saying that those impossible things will happen the equally impossibility of her stopping loving him happens.
This song is about a breakup, and she's basically saying that even though it's over she'll never stop loving him. She sas "I'll move on when the the desert floods and the grass turns blue" The desert flooding and the grass turning blue are two things that are more then likely never gonna happen - therefore she'll never move on. And then she goes on to say "Someday when I stop loving you" basically saying that those impossible things will happen the equally impossibility of her stopping loving him happens.