William Morris's lost garden of open-air 'rooms' is unearthed at the Red House

The outline of a complex sub-divided garden that could rewrite horticultural history has been uncovered at the Red House, former home of the philosopher, poet and artist William Morris. Semi-enclosed, room-like spaces inspired by Medieval paintings and Victorian notions of privacy are among the features being pieced together by the National Trust from the underlying plan of its existing garden.

Conservationists are to embark on a long-term project to restore key areas of the grounds surrounding the Gothic-influenced house, at Bexleyheath in Kent, which will continue long after it is opened to the public this July. Exploration of the interior has also thrown up some surprises. A Pre-Raphaelite wall painting depicting a scene from folklore or classical mythology has been discovered behind a built-in cupboard in Morris's bedroom.

Julia Simpson, director of the conservation project, said of the garden: "Our thinking is that what's there at the moment is far simpler than what was there originally, and bears more of a resemblance to what people who have occupied the house since Morris thought he might have approved of than what he actually did with it.

"Morris was living at the Red House in the 1860s, and what we expect to find is a series of intimate spaces divided up into 'rooms' in the style that became fashionable decades later, when Gertrude Jekyll was working with Edwin Lutyens at Sissinghurst."

Those working on the garden do not have a lot to go on. Aside from two articles about it in Country Life, one from the 1920s and the other the 1960s, they have had to rely on faded photocopies of long-ago mislaid "sales particulars" dating from 1934. But Ms Simpson is confident that they will be able to obtain a far clearer idea once they have carried out ground surveys and X-ray analysis.

Referring to the wall paintings, thought to be the work of one of Morris's long-standing collaborators, Dante Gabriel Rossetti or Edward Burne-Jones, she added: "No one had any idea they were there. People must have seen them, 40 or 50 years ago, but someone at some point built a cupboard over the top."

Although Morris only lived there briefly, from 1860 to 1865, the Red House holds a near-mythic status for Pre-Raphaelite scholars. Designed by the acclaimed architect Philip Webb, a key figure in the Arts and Crafts Movement, and described by Rossetti as "more of a poem than a house", it became the focus of a love triangle after the painter embarked on his long affair with Morris's young wife, Jane Burden.

Dr Twigs Way, a lecturer in gardening history at Cambridge University, said: "So much of Morris's writing includes his ideas on what gardens symbolise and what they should look like, so it would be fascinating to finally see what he originally did with his own."

www.nationaltrust.org.uk