Henry Hawkins Tremayne was a curate in Lostwithiel, Cornwall, and unexpectedly inherited the estate of Heligan. This large estate is one of the finest gardens of its period, containing 57 acres of planted gardens, 100 acres of ornamental woodlands, and 300 acres of rides and folly temples. Henry Hawkins Tremayne hired Thomas Gray to draw up a plan of the garden (pre-1810) and set about planting the major shelter beds that have created the gardens as they are today. John Tremayne and John Claude Tremayne carried on this work developing and planting the 57 acres of gardens and ornamental woodlands with walks and rides. They were noted horticulturists and by the end of the century had a superb collection of trees and shrubs from Japan, China, Australasia and the Himalayas many of which can be seen today.
During the First World War, Heligan House was taken over by the War Office and became a convalescent home for officers who returned from war. Few of the garden staff who fought in the war came back and, in a changed economic climate, the family decided to rent out the house and soon the garden became neglected. The house was requisitioned during the Second World War by the US army, and was later rented out as flats, still under the ownership of the Tremaynes. By this time the gardens had become so neglected that shrubs and weeds covered the small buildings, including a glass house, and much of the beauty of the gardens was lost. In the 1990s funds were raised to restore the gardens, which are now home to exotic fruits, tropical plants and a summer house.