Hart’s tongue is a fern of the spleenwort (Asplenium) genus. Finland has five native spleenwort species but hart’s tongue is native to central and southern Europe. It has handsome shiny green, narrow and wavy-edged leaves, their shape being reflected in the common name.
When conditions are suitable, with sufficient moisture and good rich soil, the slow-growing hart’s tongue can produce handsome rosettes. It also grows in rock hollows, but less luxuriantly and smaller. At Mustila the species grows on the sides of moist ditches.
To many, hart’s tongue might be more familiar as an indoor plant, as it is not often grown in Finnish gardens. In Victorian Britain ferns were fashionable and separate greenhouses, called ferneries, were built for them. Hart’s tongue is an old medicinal herb, mentioned as early as the 1400s. The scientific name Asplenium comes from the Greek, meaning “without spleen”, and extracts were used to prevent blockage of the spleen, on the basis that the spore-cases were spleen-shaped.