I don't know if she's naturally blonde or not, but I'm blonde and I'll tell you that my hair, which is about the same color as Ann's in the summer, always photographs with very dark roots as if I were a bleached blonde who hadn't gotten a touch-up in months. It's embarrassing, but it's a function of the fact that the pale hair is rather transparent. In real life it grows out a little darker than the ends, but doesn't look black as it does in photos. There is a not a thing she (or I) can do about this.
I don't think it's natural. I think she does need to touch up the roots a bit, but what do I know.