Episode 4: Brandi Carlile

For Brandi Carlile, Tom Petty’s “Wildflowers” is a north star.

The Grammy-winning singer-songwriter sits down with BBC 6 Music's Matt Everitt to explore what the track means to her - why its tenderness and message of letting someone go free has stayed with her, and how Petty’s songwriting has inspired her own. Plus: harmony, honesty and the art of writing a song that lasts.