In 1493, Sir Piers Edgecomb married Joan Durnford an heiress from Devon, and although still living at Cothele, Sir Piers created a deer park at Mount Edgecumbe. In 1547, their son, Sir Richard, built the house overlooking the Plymouth Sound.

On inheriting the property in 1667, Richard Edgecumbe began planting the garden. Celia Fiennes visited in 1698 and wrote that it was ‘the finest seate I have seen and might be more Rightly named mount pleasant‘.

Richard, 1st Lord Edgcumbe developed the outer gardens from their formal layout into an early Arcadia with the Gothic ruin (1747) and a Temple (1755) dedicated to Milton with an inscription from Paradise Lost:
A sylvan scene, and as the ranks ascend
Shade above shade, a woody theatre
Of stateliest view.

The 2nd Baron, a friend of Horace Walpole, built the Zig–Zag paths planted with arbutus, myrtles and laurustinus which William Beckford would later refer to in his letter to Lady Hamilton dated October 17th, 1781. Beckford understood the magical and spiritual effect that an Arcadian Garden could have on its visitors. He wrote: ‘Here I am breathing the soft air of Mount Edgcumbe standing upon the brink of a Cliff overlooking the Sea and singing Notturnos with Pacchierotti. [an Italian castrato singer who had been hired to sing at Beckford’s twenty–first birthday]. Innumerable Insects are humming about the Myrtles and Arbutus which hang on the steeps and are covered with blossoms. I cannot help thinking myself in an Isle of the Atlantic Ocean – to which if we believe Pindar and his poetic Brethren the Souls of Heroes are transported. Here are the very paths I ran over two years ago – the pines against which I rested – the Bank where I stretched myself out and fell into one of my happy dreams. [Was he comparing himself to Titania?]’

‘Admiral George’, the 3rd Baron and 1st Earl, continued developing the lower garden by adding the English Garden in 1770 with its Garden House and various other specimen trees including a cork oak which now sprawls over the path. Between 1786 and 1787, the Orangery was built in the Italian Garden designed by Thomas Pitt, Lord Camelford with a mermaid fountain at the centre, a gift from Lord Bessborough to his godson, 2nd Earl of Edgcumbe in 1809. Venus, Apollo and Bacchus look down on the garden from the balustraded terrace with a large bust of Ariosto filling the niche below.

William Daniel described the gardens in Voyages Around Great Britain, 1823: ‘Among all the scenes that memory could recall, none could be parallel to this….’

The house was rebuilt after it was gutted by incendiary bombs in March 1941; the 7th Earl appointed Adrian Gilbert Scott as architect. The west wing and conservatory were not reinstated, and the external walls were left bare stone rather than covered with stucco and white paint.