About 1843, H. H. Hunnewell began designing the landscape for his new estate in Wellesley. Mr. Hunnewell took great interest in planting species of evergreens from around the world that had not previously been available in the United States, and from other regions of the country not tested in New England. By 1847 he had over 2,000 trees of over two dozen genera imported from England planted on the grounds. The Italianate residence, designed by Arthur Gilman, was built later in 1851. The Hunnewell rhododendrons may be the oldest cultivated specimens in the United States, as H. H. Hunnewell started importing and planting them in the 1850s and 1860s on the grounds. Some of these original plants are likely still alive. He staged the first exhibit of large rhododendrons in the U.S., on Boston Common in 1873, which helped to make them popular in American cultivation for gardens and parks. In 1898 John Muir visited Mr. Hunnewell in the company of Charles S. Sargent, the first director of the Arnold Arboretum. Muir noted in his diary that "Hunnewell planted every tree here since he was 45 except one – an oak 250 years old." In 2010 the International Dendrology Society awarded an IDS plaque, its highest honor, to the Hunnewell estate – the first ever for an American garden.
Pinetum
The pinetum, begun in 1867, includes rare, mature specimens of Torreya nucifera, Tsuga canadensis pendula, Cedrus libani, Juniperus formosana, and Metasequoia glyptostroboides – one of the oldest specimens in the United States. In front of the 1851 residence is a massive weeping European beech. The collection of specimen trees and shrubs includes towering Pinus strobus, American white and English Oaks, lindens, tulip trees, bald cypress, and Chinese golden larch, as well as different species and cultivars of azaleas, lilacs, viburnums, hollies, weeping cherries, mountain laurel, and rhododendrons. The Hunnewell pine, Pinus x hunnewellii, is a hybrid between Eastern white pine and Japanese white pine first raised at the Hunnewell estate in 1952. ;Wellesley College Botanic Gardens The H. H. Hunnewell estate is not to be confused with the H. H. Hunnewell Arboretum in the Wellesley College Botanic Gardens at nearby Wellesley College, located across Lake Waban.
