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About
Located in Castlewellan Forest Park, The Castlewellan Annesley Garden Tree Trail leads visitors through the most historic and botanically significant parts of the garden, highlighting 26 notable trees and shrubs. These trees offer seasonal interest, vibrant colours, and botanical diversity throughout the year. Many of the specimens featured are champion trees, the tallest or broadest of their kind in the British Isles.
The Castlewellan Arboretum and Annesley Gardens is situated north of the foothills of the Mourne Mountains in Castlewellan Forest Park in County Down, Northern Ireland.
Visitor Guidelines
To help preserve the heritage and biodiversity of the garden, visitors are kindly asked to stay on designated paths and refrain from taking cuttings or seeds. These guidelines support ongoing conservation and biosecurity within this internationally important site.
A Garden with Historic Roots
Now known as the Annesley Garden in honour of the estate's former owners, the walled garden dates back to the 1740s, when it was originally laid out as a kitchen garden. In the 1850s, it was redesigned as a Victorian pleasure garden covering approximately 12 acres. Terracing, fountains, and an impressive range of glasshouses by Gray of Chelsea (1869–70) were added, while the layout incorporated a central axis linking the old and new gardens. Materials such as granodiorite from Ballymagreehan were used in its construction, giving the garden its distinctive character.
Rare Trees from Around the World
Significant exotic planting was carried out during this transformation, including giant sequoiadendron (giant redwoods), monkey puzzle trees, and flowering rhododendrons. These impressive specimens remain highlights of the garden and the tree trail today.
The Vision of Hugh Annesley
The expansion of the arboretum was largely the work of Hugh Annesley (1831–1908), 5th Earl of Annesley, a passionate plantsman who collected seeds and specimens from across the globe. His vision transformed the garden into a thriving botanical centre, complete with glasshouses, a bothy yard, three vineries, and a cool conservatory, all supplied with water systems — an impressive feat for the time.
A Living Legacy
By the early 20th century, over 3,000 species of rare and tender plants were flourishing in Castlewellan’s mild microclimate. Hugh Annesley documented the collection in his 1903 publication, Beautiful and Rare Trees and Plants. Since then, Forest Service staff have continued to add to the collection, carefully selecting new specimens to enhance its diversity. Today, the Annesley Garden spans 5 hectares, forming the heart of a 45-hectare arboretum that is recognised internationally for its exceptional range of trees and shrubs, including a significant number of champion trees.
