During a visit to the Zürich arboretum, Jonas Frei came across a nut species rarely found in Europe. The Juglans cinerea, or white walnut, is native to the U.S. and Canada and has a ribbed, oblong shell that once cracked, reveals a sweet, fleshy innard. Its presence in the Swiss enclave dates back to 1887, when the botanist Carl Joseph Schröter planted a tree that eventually produced the non-native fruits and sparked Frei’s enduring interest in the plant genus.
Based in Schaffhausen, Frei is a naturalist, illustrator, and landscape architect whose interest in botany has taken him to gardens, arboretums, and parks throughout Europe and North America. He recently spent time in Harvard’s Arnold Arboretum after being awarded the James R. Jewett Prize, which allowed him to expand his research on the walnut and explore how it’s migrated over centuries. Much of his work is focused on making science easily digestible and visually intriguing to a general audience. “Research itself really is my goal,” he tells Colossal. “I want to understand the subject and make the knowledge accessible through my writing and the aesthetical presentation of the diversity of species and cultivars.”
Shared through illustrations and flat-lay photos, Frei’s studies have recently culminated in a book devoted to walnuts and hickories, which brings together the cultural, historical, and botanical importance of these diverse plants. “I was driven not only by my scientific interest in Juglandaceae but also by my enthusiasm for the aesthetics of their habits, leaves, and fruits. The readers of my book should be able to make their own journey of discovery through the walnut family, on the tracks I have uncovered with my research,” he says.
The expanded edition of Frei’s book, which includes updates from his studies at Arnold Arboretum, is available along with posters, prints, and a similar volume focused on hazelnuts on his site. Follow his latest research on Instagram.