The Killing Tree by Rachel Keener
It's the summer after Mercy Heron graduates from high school, and she's living in the household of her domineering grandfather and a grandmother whose behavior has always been erratic--some folks even call it crazy. They've raised Mercy since her mother died giving birth to her under the June apple tree, after Father Heron locked her out and ignored her pleas for help. Mercy's days are spent working at the local diner, and hanging out with her wild best friend Della. Unlike Della, she's never seriously considered leaving the insulated community on Crooked Top mountain. Not until that summer when she meets Trout, a man who opens Mercy's eyes to a world beyond what she's known--both physically and emotionally. Their relationship must be kept secret, because Father Heron won't approve of his granddaughter being involved with a migrant worker. But when Mercy tries to escape, she'll learn just how powerful, and ruthless, her grandfather can be. And the truth of her past will threaten to forever bind her to the mountain.
New York: Center Street, 2009