"The lucky one" is a song from Taylor Swift's album Red (Taylor's version). It has been rumored to be about folk-pop legend Joni Mitchell, who famously stepped away from public life after becoming a successful singer-songwriter.
The song starts off with Taylor telling the story of a star who is looking for a better life. This star is new to town with a made up name, seeking fortune and fame. But she isn't happy because "they tell you that you're the lucky one, but you're so confused/cause you don't feel pretty, you just feel used."
She wonders why someone in her position would choose to disappear, buy a bunch of land somewhere & chose the rose garden over Madison Square. She is thinking about a quieter life where she doesn't have to deal with the constant pressure of stardom and being surrounded by people.
In this case, I believe the rose garden is a reference to a quieter life built around love. A star like her can have all the success in the world but if she doesn't have any love then her life is meaningless.
The song is a cautionary tale of how being in the limelight can be hard. It also is a reflection of how Taylor's life has changed over the years. She has not always been the lucky one and she has had to make sacrifices to achieve her dreams. She is now at a point where she realizes that being the lucky one doesn't mean being constantly in the limelight, but it does mean knowing when to disappear to enjoy your life more.