Benmore Fernery

In 1870 James Duncan, a sugar refiner from Greenock, bought the Benmore estate in Strath Eachaig, near Dunoon. A keen plantsman, he built a heated fernery there in the early 1870s, when Victorian Britain was in the grip of fern fever; the Royal Botanic Garden Edinburgh gives the date as 1874. It was costly both to build and to run. A study by David Gray, published in 2025 in the journal Sibbaldia and based on digitised archives, attributes its construction to James Boyd & Sons, the horticultural builders of Paisley.

After Duncan sold the estate the fernery declined. The Younger family, owners from 1889, gave the estate to the nation in 1924, and in 1929 the Royal Botanic Garden Edinburgh opened it as its first outstation. By then only the walls and part of the roof structure of the fernery survived, and the building remained a ruin for about a century.

Listed category B in 1992 by Historic Scotland, which described it as a rare structure integral to the gardens, it was restored between May 2008 and September 2009 under the Glasgow practice MAST Architects. The work was funded by the Heritage Lottery Fund, the Younger (Benmore) Trust, an RBGE members' appeal and private donations. It won the Glasgow Institute of Architects' conservation award in 2009, and in 2016 the same institute named it among twenty award-winning buildings.

The fernery follows the slope: rectangular in plan, it rises from a single storey to three levels as the ground climbs. Three of its thick walls are of schist rubble bedded in lime mortar; the fourth, to the east, is the natural rock face of the gully. A tall gable facing south-west and a lower north gable frame a glazed barrel-vaulted roof, originally carried on semicircular iron trusses resting on buttresses.

Visitors entered through a dark vaulted porch, with stairs on either side leading up to the middle level. Inside, an ornamental grotto arches over an oval pool, cantilevered stones serve as planting platforms and white quartz-edged paths trace a figure-of-eight route. A coal-fired boiler in a small lean-to on the west side sent warm air through underground pipes.

Before restoration the walls, gables, grotto and pool had survived, but the entrance vault had been demolished and all the original glazing was gone. The architects chose a new glazed barrel vault in modern materials, since the original structure was judged impossible to maintain, with manual ventilation through a lantern, a gravity-fed water supply and no electricity.

The fernery holds a collection of ferns from temperate and warm-temperate regions, most of them of known wild origin. More than three quarters were raised from spores at the Royal Botanic Garden Edinburgh, and some species have become rare in the wild. They come from places as far apart as the Juan Fernández Islands, the Azores, Hawaii, South Africa, New Zealand and Tasmania.

Plants singled out by the garden include the royal fern (Osmunda regalis), the tree fern Dicksonia antarctica and the Killarney fern (Trichomanes speciosum), which the garden describes as one of Britain's rarest species. Shrubs are planted among the ferns.

The fernery is in Benmore Botanic Garden, one of the Royal Botanic Garden Edinburgh's satellite gardens alongside Logan and Dawyck, in Strath Eachaig between the Holy Loch and Loch Eck, near Dunoon on the Cowal peninsula. Set in a rocky gully on the hillside, it is reached on a walk up through the garden's slopes. Allow half an hour for the fernery itself and longer for the rest of the garden, where the avenue of giant sequoias planted in 1863 is one of the best-known features. The play of light between the glazed vault and the rock face is best seen on a bright day.