Property: A house can grow on you: With a good garden, a property is much easier to sell. Anne Spackman reports

A tree house conjures up a picture of a ramshackle arrangement of wooden planks used to make a children's den. At Kingsmead House, near Badminton, the tree house is still played in, but instead of planks it has walls and a roof made of leaves. And it is large enough to accommodate visiting adults.

The Yew Tree House sits four square on the lawn surrounded by its own cottage garden. You enter through a Gothic doorway between a pair of variegated holly bushes. From the outside it looks as though the walls are 2ft thick, but that is an illusion created by the 'faux' windows. From the inside you can actually see out between the leaves. The house is formed by four great yews clipped to form this enchanting cottage, their trunks serving as pillars, ringed by knotted log seats, with the odd stone animal dotted around.

Jane, Countess of Westmorland, who is selling Kingsmead through Savills following the death of her husband, is the latest in a long line of owners who have given particular attention to the garden.

Few of us could afford the pounds 950,000 price tag that this kind of house commands. But gardens matter all the way down the property ladder, from the most expensive house on the market in Britain - the Rectory in the King's Road, Chelsea, whose two acres contribute to the pounds 25m asking price - to the terrace of the smallest one-bedroom flat. A garden is our chance to create a magical place, somewhere away from the bills and the washing machine, somewhere to escape to, like little Mary Lennox in The Secret Garden.

One of the best places for re-enacting Frances Hodgson Burnett's novel is at the Tower House in Leeds, Kent. The house itself is a late Victorian period piece, from the Thomas Jeckyll fireplaces to the specially commissioned wallpaper. Outside, gravel paths and archways lead through a sequence of garden scenes. The conifer walkway leads to a water garden with cobbles and rockery; a trellis of wistaria and climbing roses lead to the rose garden. In all there are five and a half acres of garden at the Tower House, which is being sold by Strutt & Parker for pounds 550,000.

Coming slowly down the price range, Hamptons is selling a garden more famous than the house it surrounds. In it, one summer's night in 1924, Beatrice Harrison played some Dvorak on her cello, accompanied by an ode from a now famous nightingale. Foyle Riding became the scene of a landmark in the history of broadcasting.

The Harrisons discovered the rent for the original house on the site at Limpsfield in Surrey had been paid in 'gillyflowers'; these clove-scented pinks now grow in abundance in the borders of Foyle Riding, which is for sale for pounds 400,000.

Another piece of garden history on the market is the Great Dovecote of Westington in Chipping Campden, Gloucestershire. This listed stone building has 1,000 nesting holes reached by a ladder from the central stone table. It is being sold as one lot with the Woolbarn, a three-bedroom cottage, for pounds 175,000 by Jackson-Stops & Staff in Chipping Campden.

In cities, gardens of any size are a rare commodity. In those with ancient historic centres they command an even greater premium. In York, Carter Jonas is selling 23 Ogleforth, one of a row of three houses with a view of York Minster. Originally the house had an asbestos-covered car port at the back. But the current owners have used the creative flair evident in the house's interior to turn the space into a charming city garden, with steps leading down from a plant-strewn balcony to a pretty brick courtyard. The house is on the market for pounds 185,000.

Edward Waterson of Carter Jonas said a garden could add a good 10 per cent to the price of a house in York. In the case of a large family house in the city centre, a large garden would push the price up from pounds 200,000 to pounds 300,000-plus. 'You can get a super house at a reasonable price,' he said, 'but without a garden, it can be difficult to sell. You have to find an affluent couple with no children.'

London is ringed by 'village' suburbs where families tend to migrate in search of houses with gardens for their children. The traditional London garden is a 40ft narrow rectangle with an awkward dog-leg at the side of the kitchen. Ealing, in west London, is blessed with a number of detached and semi-detached houses offering gardens front and back.

Winkworth is selling three houses in the area with outstanding gardens. One is a former alms house set back from the road inside a large walled garden. The four-bedroom house is on the market for pounds 295,000. According to Andrew Grice, sales director at Winkworth's Ealing office, the asking price without the garden would be about pounds 210,000.

Mr Grice said about 80 per cent of house-buyers in the area considered a garden very important: 'It makes a big difference if it is a south- or west-facing garden. It adds about 1 or 2 per cent to the price and about 40 per cent more people will go and look at the property.'

A five-bedroom house in Denbigh Road, W13, on sale for pounds 395,000, has an 80ft, west-facing garden. The present owners found a pile of numbered stones at the bottom of the garden and started to stack them in numerical order. They turned out to be a Victorian folly.

One of the strangest cases in which a garden was crucial to the sale of a property was in Finchley, which is attracting a growing number of buyers from Hong Kong. The Hong Kong Chinese take matters such as the position of the garden, the direction the lavatory faces (it should point eastwards) and even the number of the house very seriously indeed. Winkworth was selling a house with the number 43, which is apparently lucky, and with an acceptable lavatory. The clincher was the client's discovery that the garden faced south-west, lucky for people with his birth sign. He offered pounds 20,000 more than any agent thought the house was worth, only to be gazumped by another Hong Kong Chinese impressed by the same features.

(Photograph omitted)