A radical vision of the country

If you're looking for an opportunity to wallow in nostalgia, don't come to Harewood House. This stately home is generating new thinking about the arts and the environment

"There are advantages for an artist working at Harewood", says Diane Lascelles. "How many galleries can offer you a Capability Brown landscape as a canvas?" The landscape in question, complete with ornamental lake, flocks of sheep and distant prospects of moor and dale, surrounds Harewood House, one of the great "treasure houses of England" and seat of the 7th Earl of Harewood - the Queen's cousin and Diane Lascelles' father-in-law.

Located in unspoiled country near Leeds, Harewood is essentially a Georgian creation. Lord Harewood's ancestor, Edwin Lascelles, began building the present house in 1759. He brought in Robert Adam to create some of the most sensational interiors of the age, while Thomas Chippendale (a local boy, born down the road in Otley) was given the commission of a lifetime furnishing the house. After many tribulations - two thirds of the land had to be sold to pay off death duties when Lord Harewood inherited in 1947 - the future of the house, the fabulous contents and "heritage" landscape now looks secure in the hands of a charitable trust. Nearly 300,000 visitors a year - a figure which bucks the general trend of declining visitor figures - help to secure the future of one of Yorkshire's key cultural monuments. Harewood House is the only private house to enjoy full museum status - a factor which has helped the Harewood House Trust score in the Lottery stakes.

Diane Lascelles (who works under the name Diane Howse and considers herself "first and foremost an artist") has never lost the sense of amazement she felt when she first discovered Harewood more than fifteen years ago, having married film-maker David (Viscount) Lascelles, heir to the earldom. "It was extraordinary to see a room full of Turners, knowing that Turner stayed here and painted here. He was an innovative artist, "modern" in his way - and the the Lascelles backed him."

In the 18th century, the Lascelles, an old Yorkshire family enriched by the West Indies trade, could afford land art on the grandest scale. The old village of Harewood, except for the church, was razed to the ground and rebuilt a mile away, opposite the triumphal arch into the park, to improve the view from the house. Today, Diane Lascelles continues the family tradition with more modest resources. A decade ago, she secured a below-stairs space, opening off the terrace gardens, and turned it into the Terrace Gallery. The first exhibition, "Images of Paradise", featured the work of around 65 contemporary artists. The Gallery has since hosted nearly 40 exhibitions of modern and contemporary art. This week, artist Kate Whiteford is launching a show there - and on the green hillside across the valley. She has cut into the turf a "landscape drawing" on a huge scale, its serpentine lines a clear reference to the work of Chippendale - the subject of an exhibition this season.

The Harewood art programme has long outgrown the Terrace Gallery (itself due to be replaced by stylish new premises carved out of the stables block). Last year, Anya Gallacio's installation of flowers, sandwiched between sheets of glass, and left to quietly decay in Harewood church caused some comment among local people (and had to be removed when the rotting blooms began to stain the historic floor). This year, nonetheless, artist Richard Devereux is showing an installation in the church.

The extensive walled gardens are another focus for artists. Long disused, these spaces have always fascinated Diane Lascelles. Last year, working with Andy Halley and guest curator Tom Clark, she turned the largest of them into a "spiral meadow", with a great swirl of wild flowers and meadow grass a hundred feet across. She says: "It was a delight to talk to elderly people, who told me that the spiral reminded them of the meadows they knew in their youth."

The interactive sound installation being created by artist-in-residence Sophie Benson and others this summer in another of the walled gardens could be more disturbing in effect. Don't people come to country houses to wallow in nostalgia - to be reassured that some things never change? For many Harewood visitors, it is family history and Royal connections which are the draw.

Nobody has to come into the Terrace Gallery, says Diane Lascelles, any more than they are obliged to visit the Bird Garden or the highly-rated adventure playground. But an increasing number of visitors do look in and some linger. "I want to surprise people, rather than shock them," she says. "I'm not into patronising our audience - I show what I believe in and if that broadens horizons, I'm pleased. If people come to see Chippendale and get to know about the work of, say, Helen Chadwick, we are succeeding."

The support of Lord Harewood, says Diane Lascelles, has been "a constant encouragement". A key figure in the post-war arts scene - he edited Opera magazine, ran the Edinburgh Festival and English National Opera, and was effectively the founder of Leeds-based Opera North - George Harewood caused a minor sensation back in the Sixties by installing Epstein's colossal nude figure of Adam in the entrance hall at Harewood. During his time, the ethos of Harewood has been far removed from the self-indulgent philistinism which some associate with "great" houses and old families. Music has always figured strongly and regular concerts are now being supplemented by dance and poetry workshops. Harewood's visual art programme is linked to the work of the Henry Moore Centre in Leeds, the Dean Clough Studio in Halifax, the Yorkshire Sculpture Park and other institutions. One function of the Terrace Gallery has been to underscore the strength of the modern tradition in a region which produced artists of the stature of Moore, Barbara Hepworth and Patrick Heron. Last year, there was a major show covering the links between Yorkshire and the St Ives School.

Harewood remains a "real" country house in the sense that the family retains a private estate, run as a business by David Lascelles. For Diane Lascelles, the commercial and "heritage" sides of the Harewood operation are inseparable. "People have lived here since the Iron Age", she says. "There's a medieval castle and the foundations of a 17th century manor house in the park. The present landscape is relatively 'modern': the Lascelles have only been around for 250 years. What we're doing this year is to stress its holistic quality - to get people to think about the connections between art and nature, tradition and change." The landscape itself is the greatest work of art of all and Diane Lascelles' passion for hedgerows, forestry, wildlife and even the lichens growing on the castle walls is anything but affected. Some visitors may be mystified by Kate Whiteford's "sofa on the hill" and the weird noises emanating from the walled garden - not to mention the floating art work to be seen on the lake later in the year. But the Harewood message is that none of it is really new. What has changed is the context of a Britain where green space is disappearing at an alarming rate for housing, superstores and roads. We need to understand the real cultural significance of the landscape to appreciate the implications of its loss. In other words, if you are looking for reassuring nostalgia, avoid Harewood. Once through the arch and into the park, you are face-to-face with a surprisingly radical vision of the country house as a generator of new thinking about the arts and the environment.