Yarrow spent most of her childhood in the woods, pretending to be characters from books. She especially liked the ones where children had to survive on their own. In 2009, she went to Oxford to study English and French Literature, where she discovered that the Botanic Garden was the perfect place to revise for exams. After university, she became an English teacher where she especially enjoyed taking children outside to write stories. Yarrow now works for the RSPB in the New Forest, helping people find secret paths through the woods, and fulfilling her lifelong dream of learning to use a chainsaw.