Fez has authored and illustrated a number of books, primarily exploring the importance of plants and insects to the development of human culture and religion. These books include Bees: A History, published 2018, Folk Magic and Healing, published 2019, Botanical Curses and Poisons, published 2021.

Fez focuses on the significance of parts of our ecosystems that are often overlooked, such as common weeds and hedgerow plants, and aim to raise awareness of their vital importance to the health of our planet. Through donating a percentage of sales to environmental charities, she has raised thousands towards local conservation efforts.