Adder's Tongue Ferns at Fell's Field

Adder's Tongue Ferns at Fell's Field

An incredible 764 adder’s-tongue ferns were recorded at Fell’s Field in 2026. This is the highest number recorded at the site since the species was first discovered there in 2014.

Fell’s Field was donated to Manx Wildlife Trust in 1998 and historically was mainly used for cattle grazing. Over the last 28 years the field has been transformed into a beautiful wildflower meadow. 

Initially, vegetation from Close Sartfield Nature Reserve was cut and transported to Fell’s Field, where it was allowed to dry and drop wildflower seeds. Since then, careful management, including the control of certain problematic species, has created a rich habitat for different species. The meadow is cut for hay in the summer and then grazed by sheep over the autumn and sometimes into winter.

Today, more than 100 species of plant are regularly recorded within the field and its surrounding hedges. Heath-spotted orchids started to appear in small numbers in 2001, and this number has grown over the years, alongside common spotted orchids and the occasional northern marsh orchid. In 2026,  three greater butterfly orchids were found. 

Adder’s-tongue fern was first recorded at Fell’s Field in 2014, when 94 plants were counted. Initially always found in one area of the field, they were subsequently found in new places and are now thought to be throughout the meadow. It is a small and easily overlooked fern, which is why surveys take place in late April or early May, before the meadow vegetation becomes too tall. 

Unlike many of the ferns we associate with woodland and hedgerows, adder’s tongue fern thrives in grasslands and meadows and on sand dunes. It is so-called because the spore-bearing stalk is thought to resemble a snake’s tongue. Each plant has a single undivided leaf, and the spore stalk arises from the leaf stalk. There is usually a single spore stalk but there can be two or three. 

Adders Tongue Fern
Mutant Adder's Tongue Fern

The leaf blade may be present without a spore stalk. The plant does not always send up a leaf and can survive for several years under the soil, nourished by an association with soil fungi. Interestingly, adder’s tongue-fern is considered a good indicator species of ancient meadows and yet Fell’s Field was ploughed in 1998.

 

Adder’s-tongue fern has quite a restricted growth around the Island. Historically, it has been documented at four other MWT nature reserves and each year surveys are undertaken to ascertain a rough idea of numbers. Recently, it has been recorded at two further sites, both willow dominated curragh, where at a distance, it almost looks like wild garlic.

 

 The record breaking number at Fell’s Field is a wonderful example of how careful, long-term management can help create and maintain valuable habitats for native plants. Fell’s Field is a one-hectare nature reserve with controlled access to help protect this important meadow habitat and so the reserve is open by appointment only. If you would like further information on Fell’s Field, please contact the MWT Reserves Officer, Tricia, at tricia@mwt.im.