The Tregothnan garden was first described in 1695 by intrepid traveller, Celia Fiennes when visiting Hugh Boscawen, her kinsman by marriage. In her book 'Through England on a Side-Saddle', she wrote: "About the garden's gravel walks round and across."

The character of the present garden was formed by Evelyn Boscawen, the sixth Viscount Falmouth, and his brother, the Honourable and Reverend John Townshend Boscawen, the rector of nearby Lamorran. They brought rhododendrons, rare trees, shrubs and camellia plants into the garden over a hundred years ago - thought to be the earliest plantings of camellias in the open.

Canon Arthur Boscawen of Ludgvan Rectory, the son of the Rector of Lamorran, also introduced many new plants to the garden in the early years of the last century. The present Lord Falmouth's grandmother was a distinguished gardener who, for many years, was Chairman of the Swanley Horticultural College for Ladies. Lord Falmouth's mother was also a knowledgeable botanist and they added to the beautiful and rare plants at Tregothnan. The late Lady Falmouth, who started life as a horticultural student at Studley College in Warwickshire, became a working gardener and continued this long tradition and in turn the Honourable Evelyn Boscawen is now in residence and continuing the tradition with dynamism.