The story is about a teenage girl who doesn’t remember her past.  She moves to a new town with her parents.  They live in a big house with a hedge around it.   There is a mystery involved with the house.  I don’t remember the events in the story, but somehow her life is in danger and I think she starts remembering things from her past and possibly the house.  Her parents might not actually be her parents.  At the end, someone to kill her at the house where she is alone because whatever she is starting to remember will expose what they have done.  She finally remembers everything during the fight? for her life.  I read this book probably in the late 60’s early 70’s.