The original provenances of sweet fern are extremely poor, the nearest equivalent would be a dirt road. Even though you might not take this as a planting rule, you might get an idea of the right conditions. In Mustila, the site has been prepared by mixing in more sand. Two sweet ferns are growing in Tuijalaakso (the Thuja valley), along a path on a sunny spot near the pond. They have been grown from seed collected from Ontario, Canada, at the northern edge of its range. Even a soft touch of the leaves brings out the strong, aromatic scent.