Paradise island: Lady Walton's Italian Eden

Susana, Lady Walton, is unlikely to forget her introduction to Ischia. She and her husband, Sir William, had just raced their Bentley from London to Naples, and here she was, at the wheel, about to drive the huge saloon onto two wobbly planks hung across the stern of a small ship for the perilous voyage to the volcanic island somewhere out there in the Mediterranean.

First the Captain had to move two old cows, the island's weekly supply of meat, and then, to cries of "Avanti! Avanti!" ordered her up the precarious ramp. She could see nothing above the bonnet of the Bentley except sea, and was convinced she would plunge straight off the quayside into the water and drown. The Bentley hung so low over the stern of the steamer that Sir William suggested putting a cork in the exhaust to stop the salt water washing in. Just as they were about to set sail Italian police arrived and said they didn't have the correct papers and would Lady Walton please drive the car back off the ship onto land again.

In her native Spanish she informed them that she wouldn't and ordered the captain to set sail. She might have been safer if she had stayed on dry land. This was 1949 and there were still German mines in the Bay. Life didn't get any easier when they landed. Their first home had a perilous electricity supply, the kitchen had no water, rats infested the ice-house where they kept their food, and silver-coloured rubber curtains made from old barrage balloons replaced glass in the windows. The Bentley was also the only car on the island. There were no petrol pumps so they had to bribe local fishermen for their supply. And this was the idyll Sir William had charmed her away with, saying life would be so much better than the sophisticated society she was enjoying in Mayfair.

From where she is sitting today on the cool terrace of La Mortella, her mountainside home, with its sweeping panorama of the Tyrrhenian Sea and the volcanic peak of Mount Epomeo, high above the tropical canopy of palm, fern and pine, Lady Walton lets her gaze rest for a moment on her creation. The garden is scented by lemon and jasmine, the soundtrack exotic bird song and gurgling fountains. This is about as close to Eden as it gets.

La Mortella was voted the best garden in Italy in 2004, in the country's most prestigious competition, Il Parco piu bello d'Italia, by a panel of international judges, experts in gardening landscaping, including Judith Wade from Britain. Each year around 60,000 people come here to see how a parched, dramatic boulder-strewn valley, open to the full glare of the sun, below a steep cliff covered in the common myrtle, the mortella of La Mortella, has over 40 years been transformed into a horticultural masterpiece.

There are rare waterlilies from the swampy reaches of the Amazon, lotus pools and exotic orchids; you climb from a lush valley rainforest, sprinkled with soaring water-jets and sparking rivulets, to sun-baked zones at the summit where you discover a Thai temple ringed with nodding blue agapanthuses. You might even stumble startled across the visual joke of a bronze crocodile about to pounce from its poolside lair. Lady Walton has needed all the resolve she showed in first coming to Ischia.

The Waltons' great friend Sir Laurence Olivier begged them not to buy the site. "It's just a stone quarry," he said. "You'll never make anything of it." But Susana fell in love with the dramatic impact of the spot and while Sir William composed, she moved earth and rock, planting, propagating and irrigating. (Before they married, Sir William wrote the music for Olivier's three Shakespeare films, Henry V, Hamlet and Richard III, as well as Crown Imperial for George V's coronation. While on Ischia he composed Orb and Sceptre for Queen Elizabeth's coronation and his most ravishingly romantic work, Troilus and Cressida.)

"I talk to the plants every day," Susana says. "Many visitors come over on the boat for the day from their hotels in Sorrento. I take them on a tour of the garden and when we reach the Gingko biloba, our most ancient tree, I make them take their hats off as a sign of respect. This is the oldest flowering plant in the world, unchanged for 200 million years, once thought to have been extinct, the sole survivor from the carbon age." In a garden of exotic, voluptuous flowers, the queen of them all is undoubtedly the Victoria amazonica, the largest waterlily in the world, grown in very few places outside the sluggish backwaters of the Amazon.

"It's a very clever plant," says Lady Walton with a mischievous gleam. "It changes sex overnight from male to female, turning from white to crimson. "The blooms are the size of a dustbin lid and the huge, pie-shaped leaves* *12ft in diameter. A child could stand on them." Victoria was the star of her garden at the Chelsea Flower Show six years ago. She took the plant in a heated truck all the way across Europe. She had written to various travel companies asking them to include La Mortella in their tours but they didn't reply. Then the BBC made a film about it and when Chelsea opened the crowds flocked to her garden. After that the tour companies changed their tune.

Sir William died in 1983. His ashes are buried in the garden. He fell for Susana in Buenos Aires when she was 22 and he was 48. He saw her at a press conference and as soon as they were introduced asked her to marry him. "He hadn't even heard my voice," she says "But he said he had a vision of how the rest of his life would be." The home they shared is sand-coloured and cut into the rock high above the valley floor. The locals called it la caserma (the barracks). Their garden designer, Russell Page, likened it to a Minoan palace. Everywhere you look there are memories of the great man. Poignant black-and-white Cecil Beaton photographs of Walton at Oxford, his gleaming medals and insignia, show posters from La Scala, Piper stage sets, the piano he composed on...

Later that night there was to be a concert in an air-conditioned, state-of-the-art auditorium. Two young Italian musicians from Naples were going to perform Walton's dreamy sonata for violin and piano; the same two young women who played for Prince Charles when he came here in the early Nineties. The Walton Foundation, of which Charles is patron, encourages young musicians from all over the world, offering them accommodation and a concert hall to perform in, all funded by the garden. At Il Moresco, the hotel where I am staying, Lady Walton is revered as the uncrowned queen of Ischia, quite an honour for a foreigner on this clannish, gilded isle. Much of The Talented Mr Ripley was shot in Ischia after the director Anthony Minghella had scoured Amalfi searching for a recreation of the glamorous il boom Italia, the Italy of the Fifties. It is a Hollywood fantasy. Narrow cobbled streets hung with washing; the splutter of lipstick-red Vespas; bell towers, baroque churches, belvederes, rococo colonnades, black-shawled old ladies selling fruit in the morning market; all in the shadow of the 14th-century Castello Aragonese, an island fortress 600ft above the waterfront, joined to the mainland by a narrow causeway.

It was against the forbidding backdrop of this castle that Minghella set the murder of the golden-haired dream boy Dickie Greenleaf (Jude Law) by the relentless, homosexual, social climber Tom Ripley (Matt Damon) after he was lured out to sea in a rowing boat. Most of the cast of Ripley stayed at the Il Moresco. It has a wonderful natural spa that Gwyneth Paltrow is reported to have enjoyed. There are three heated pools and the mineral-rich water comes straight from thermal springs, one in a spruced up old hidden grotto, where for centuries wine was kept cool.

Susana has no time for the lotus-eating life enjoyed at Il Moresco, however. At 79 she still possesses a demonic, restless energy, always taking on new projects. The latest is the building of a 450-seat amphitheatre in which to perform Walton's music, situated at the peak of the garden with spectacular views of the sea and the town of Florio. It opens next Saturday, 2 September, with a performance of Henry V by the Ealing Symphony Orchestra conducted by John Gibbons. It will also be Lady Walton's 80th birthday. "There will be a glass of champagne for everyone," she promises.

TRAVELLER'S GUIDE

GETTING THERE

The writer travelled with Elegant Resorts (01244 897515; www.elegantresorts.co.uk), which offers seven nights at Il Moresco Hotel, from £825 including breakfast, return British Airways flights from Gatwick to Naples and private car/hydrofoil transfers to and from Ischia. Besides BA's Gatwick-Naples flight (0870 850 9850; www.ba.com), BMI (0870 60 70 555; www.flybmi.co.uk) flies from Heathrow; easyJet (0905 821 0905; www.easyJet.com) flies from Stansted.

To reduce the impact on the environment, you can buy an "offset" from Climate Care (01865 207 000; www.climatecare.org). The cost to the environment of a return flight from London to Naples, in economy class, is £2.70. The money is used to fund sustainable energy and reforestation projects. Ferries and hydrofoils depart frequently for Ischia from Naples with the following lines:

Snav (00 39 081 428 5555; www.snav.it), Alilauro (00 39 081 497 2222; www.alilauro.it), Volaviamare (00 39 081 497 2222; www.volviamare.it), Medmar (00 39 081 551 3352; www.medmargroup.it), Caremar (00 39 081 017 1998; www.caremar.it).

STAYING THERE

Il Moresco Hotel, 16 Via Emanuele Gianturco (00 39 081 981355; www.ilmoresco.it).

EATING & DRINKING THERE

Zi Nannina a Mare, Lungomare C Colombo 1 (00 39 081 991350; www.zinannina.com).

VISITING THERE

Giardini La Mortella, Forio, Ischia (00 39 081 986220; www.lamortella.it). Open 9am-7pm weekends, Tuesday and Thursday; admission EUR10 (£7).

There is an excellent restaurant and souvenir shop attached to Lady Walton's garden. Castello Aragonese, Ischia Ponte ( www.castellodischia.it). The fortress has been a jail, a hiding place for Moorish pirates, and was once bombarded by Nelson.

SHOPPING THERE

Di Meglio La Ceramica, Via Roma 42, Ischia Porto (00 39 081 991 176; www.ischiaceramiche.it).

MORE INFORMATION

Ischia and Procida Tourist Office: 00 39 081 5074211; www.infoischiaprocida.it

Italian Tourist Board: 020-7408 1254; www.italiantouristboard.co.uk.