Griffiths will be the International Hay Festival Fellow for the next 12 months, visiting all our festivals around the world. Her visionary and poetic work explores her interest in nature, anthropology and art. Her books include Kith: The Riddle of the Childscape, Wild: An Elemental Journey, Pip Pip: A Sideways Look at Time, and her fictionalised hymn to Frida Kahlo, A Love Letter to a Stray Moon. She talks to Peter Florence.