Terrace glasshouses, Annesley Walled Garden (Castlewellan)

The Annesley family bought the Manor of Castlewellan in 1741. The walled garden was laid out under William Annesley, then enlarged under the 4th Earl, William Richard (1830-1874), for whom William Burn built the castle in 1855-58 and designed the garden terracing in 1860. The official site describes it as then a pleasure ground with extensive glasshouses, open to the public on Mondays and Thursdays by 1871. An account of that year describes the terrace as a recently erected range of glasshouses, with a stove, three vineries and a cool conservatory; the vineries and conservatories are attributed to Gray, of Chelsea.

When the 4th Earl died in 1874 his brother Hugh (1831-1908) inherited the demesne. With his head gardener Thomas Ryan, appointed in 1881, he built up a collection of trees, shrubs and exotic plants of international repute and had more glasshouses added: there were said to be 22 by 1900, so many that Country Life journalists spoke of long aisles of glass. An amateur photographer, the Earl left pictures of his glasshouses that now guide their restoration.

The demesne declined after 1908 and the death of his son Francis in 1914; the state bought it in 1967 and opened the forest park in 1969. A garden-history blogger found them in sad condition in 2010; a first restoration (2012-14) left them empty for years. A £5.5 million project launched in 2021, funded equally by the National Lottery Heritage Fund and the council, restored them fully: the Rock House, the last of the three, received its final panes of glass before the garden reopened on 7 March 2026, after almost two years of work and repairs to damage from Storm Éowyn.

The three glasshouses occupy the terrace of the walled garden, at the foot of its high wall, above a stone balustrade that overlooks the arboretum. The garden was walled in several stages; under the 4th Earl it was extended to 12 acres with the wall running all the way round, while the terraces were designed by Burn in 1860.

The layout is symmetrical: a central block divided into three sections, whose sloping sides housed vines, flanked by two matching gable-ended houses. At the west end the stove house held a large heated tank for water lilies; at the east end the cool house, or Rock House, was arranged around a central bank of rockwork. The 1871 account attributes the vineries and conservatories to Gray, of Chelsea, a name that one study links to James Gray, a maker of boilers and installer of glasshouses for large estates. According to the council, the three glasshouses measure from 63 to 145 m².

In the nineteenth century these glasshouses served cutting-edge horticulture. According to the Gardeners' Chronicle of 1891 the vineries bore Muscat and Black Hamburgh grapes; the stove house held bamboos, figs and a flowering Schubertia grandiflora in 1896 and, according to The Garden in 1895, a water-lily tank. The horticultural press adds that in spring the Rock House filled with 6,000 forced 'Countess of Annesley' narcissi, alongside begonias.

Today, according to the council, the glasshouses are becoming a home again for heat-loving and tender plants, due to be fully replanted by early summer 2026; in April 2026 Tourism Ireland spoke of glasshouses in bloom with heat-loving plants. The garden also has the longest double herbaceous borders in Northern Ireland, and its arboretum received the International Dendrology Society plaque in 2018.

The glasshouses line the terrace of the Annesley Walled Garden, about a fifteen-minute uphill walk from the main car park of Castlewellan Forest Park. The garden is on a slope and has steps, but a platform lift serves the terrace. One to two hours is enough for the walled garden and its glasshouses. Magnolias flower in March, the rhododendrons of the Rhododendron Wood in April, the double borders in summer, followed by autumn colour. The arboretum, the lake and the Peace Maze, a maze of 6,000 yews, lie close by.