Sir Harold Hillier Gardens

Arboretum in England

The Sir Harold Hillier Gardens is an arboretum comprising 72 hectares (180 acres) accommodating over 42,000 trees and shrubs in about 12,000 taxa, notably a collection of oaks, camellia, magnolia and rhododendron. The Gardens are located northeast of the town of Romsey in Hampshire, England, and were formerly known simply as the Hillier Arboretum, founded by nurseryman Harold Hillier in June 1953 when he acquired Jermyn's House and its grounds. The arboretum was given to Hampshire County Council in 1977 to be managed as a charitable trust. Sir Harold Hillier was knighted in 1983, just two years before his death at age 80 in 1985.

Run as a registered charity, the Gardens are continually developed to further Sir Harold’s philosophy of horticulture, conservation, education and recreation. The patron is Roy Lancaster, who was the first curator. A team of 18 experienced horticulturalists and arborists look after the collection alongside students and a team of 200 volunteers.

Sir Harold Hillier Gardens has one of the largest collections of hardy trees and shrubs in the world and is famous for its collection of rare plants.

Sir Harold Hillier Gardens has the most comprehensive collection of Champion Trees in Britain and Ireland with 611 trees that are considered to be the largest, finest, or most rare of their species, as recorded by the Tree Register of the British Isles in 2020. The collection includes Metasequoia glyptostroboides, from the original batch of seed received by the Arnold Arboretum from China and distributed in 1948, its first introduction to the West. The young shoot is the emblem of the Gardens.

Sir Harold Hillier Gardens started a hypericum trial in 2014. This three year trial was in association with the Royal Horticultural Society and led by curator David Jewell. The aim of the trial was to establish garden worthiness, resolve any naming problems and assess their medicinal properties. The trial included approximately 65 different types of plants. The hypericum lancasteri, grown at the Gardens, is named in honour of patron Roy Lancaster. These trial grounds can be visited in the Gardens and are located behind Jermyn's House.

Besides growing many plants rare in cultivation, the Gardens grow over 200 threatened plant species and participates in a variety of conservation programmes, including collaboration on biodiversity projects on a local, national and international level. At a press day in 1964, a journalist asked Sir Harold what he thought of the fledgling garden plant conservation movement. “I shall tell you what I think,” he replied. “Whilst other people are talking about it I am doing it, I am planting, planting, planting and I would urge others to do the same.”

The pavilion was opened in 2003. The elegant single storey complex was designed by Hampshire County Council Architects, and has won the SCALA award for the best local authority designed building in the UK. The building is a complementary mix of modern and traditional materials. Dedicated to the memory of Queen Elizabeth The Queen Mother and visited in 2003 by the Queen. The Visitor Pavilion hosts a gallery space, ticket desk, membership desk, restaurant, gift shop and purpose built education facility.

The original house here could have been built in the early 18th century. The land in 1724 was owned by Farmer Jarman. After being used as a smallpox hospital and inoculation centre in the 18th century. It passed through a number of different owners until acquired at auction by the Hillier family in 1951. The family took up residence in June 1953. The building now houses the administrative offices for the Gardens, restaurant and tea rooms.

The Herbarium is located within Jermyn’s House and was founded in 1995 to accommodate specimens collected by Sir Harold Hillier. It was officially opened by Dr Nigel Taylor, Curator of the Royal Botanic Gardens, Kew. The Herbarium houses a particularly large collection of Quercus and it is the official repository for the International Oak Society. It holds around 8,000 specimens including specimens that are wild collected seeds or cuttings, from America, Australia, China, Japan, Malaysia, Mexico, New Zealand, South Korea and Taiwan. It is open for research purposes by appointment.