What is significant about the rosebush outside the prison door in the book the scarlet letter?

It's been along time since I had this in cl, but it has to do with the contrast between the rosebush and the prison. I remember that it is suppossed to be a symbol that life persists and is beautiful outside the prison doors. Inside, however, it is not so. Life can flourish and grow outside the prison. It shows the meaning of what prison is - a deathly solitude that essentially stops life.