The Arboretum is reputed to have been planted in 1914 just before the start of World War I. The story goes that the majority of exotic trees, many of them rare specimens, were delivered just before the Estate gardeners left to fight for their country. Planting was done hurriedly in a somewhat haphazard fashion in the expectation that they would be home by Christmas to implement a better planned planting scheme. However, the war continued until 1918 and the trees remain in their unusual positions to this day.
The Arboretum has a large number of specimen trees including a swamp cypress, cork oaks, a lantern tree, an umbrella pine, a ginkgo and a liquidambar. The area is at its best in spring and early summer. A small patch of acid grassland near the main entrance produces an impressive display of orchids and there are many varieties and colours of azalea and rhododendron cultivars which were presumably collected at the beginning of the last century.
Restoration work in the Arboretum includes pruning the rhododendrons and azaleas that are overgrown, mowing and the continual task of keeping the bracken under control.