The Dartington Hall Gardens mainly date from the 20th century but incorporate the remains of a medieval landscape on an estate that can be traced back as far as the 9th century.
The remains include a yew tree that is at least 1,500 years old. The Dartington Hall Trust has asked Pearson to sensitively reimagine the gardens.
Pearson said: "I was aware of Dartington’s reputation as a centre of holistic living and arts education long before I first visited. In the space of forty years Dorothy and Leonard Elmhirst’s radical, new approaches to farming and land management, and their integration of art, craft and design into daily life, created a progressive and liberal community that has been incredibly influential.
"The opportunity to engage with the estate as it starts on a new path of development and enhancement is hugely exciting. We are very much looking forward to starting the process of making the estate as accessible and functional as possible, reconnecting it with the agricultural and woodland landscape that surrounds it.
"We are particularly inspired by the opportunity to refresh and reinvigorate the historic gardens to make Dartington known again as a centre of best landscape and garden practice."
American designer Beatrix Farrand (1934-39) who also designed campuses for the White House, Princeton and Yale, respected British designers Henry Avray Tipping (1925-30), Percy Cane (1945-c1960) and Georgie Wolton (1992) and Danish-born Preben Jakobsen (1985) have also previously worked on the garden.
Dartington Hall Trust CEO Rhodri Samuel said: "Dan is the next in line of a series of world class designers who have helped to shape our beautiful gardens at Dartington Hall. Great gardens are living, evolving places and Dan’s brief combines respect for the past with opportunities to innovate and excite. I cannot think of a more sensitive and imaginative designer to entrust this project to."
Dartington Hall Trust Estate Manager John Channon said it had been 70 years since any major work had been carried out.
"Sadly, many vistas to the surrounding Devon countryside have been lost due to mature plant growth and some of the pathways are no longer practical. It’s time for a refresh, to look at the gardens as a whole and how they harmonise with what’s around them – for people now and for future generations to enjoy."
Pearson is expected to spend a year on initial plans and then deliver a masterplan over several years as funds are raised.