Lady Susana Walton: Composer’s wife who created one of the world’s greatest gardens

On the surface Susana Walton's life was the stuff of Hollywood fiction: feisty Latin society girl meets famous British composer; it's love at first sight and he whisks her off to the high life and a Mediterranean paradise. But darker currents flowed beneath the dazzling exterior.

Susana Gil Passo was born into a landowning Buenos Aires family in 1926 and might have been expected to follow the conventional path of the well-off porteña; good schooling, strategic marriage and easeful life as a gracious hostess. But she was made of more independent stuff: at 22, in the teeth of family opposition, she took a job – a radical gesture in a society where girls her age were chaperoned – with the British Council in Buenos Aires. Her English was fluent: her father, an anglophile lawyer, made sure his children learned English before their native Spanish.

William Walton, not yet knighted but already renowned as the composer of Façade and Belshazzar's Feast, was part of a delegation visiting Buenos Aires for a Performing Rights Society conference; Benjamin Britten was another member. As soon as Walton saw her, at a press conference she had organised, he knew this was the woman for him and told Britten: "I think I'll marry that girl over there". At a reception that evening he walked over and said: "You will be very surprised, Miss Gil, to hear that I'm going to marry you". She assumed he was drunk: "He hadn't even heard my voice," she recalled. "But he said he had a vision of how the rest of his life would be."

Susana was 22, Walton 46; she was naturally taken aback by the immediacy of his approach, her family appalled, his colleagues sceptical – but every day for two weeks he repeated the proposal. When he changed tack and said he would never ask again, she agreed, and in December 1948, within two months, they were married. Walton swept his sweetheart back to Britain in triumph, where she now discovered her new husband's reputation as a philanderer.

Before his trip to Buenos Aires, Walton had been living with Alice, Viscountess Wimborne; with commendable candour he called it "scrounging". But Walton had enjoyed the run of society women long before her death, from cancer, earlier in 1948. As Susana got to know her husband's friends, it must have seemed as if he had already slept with virtually every woman she met. Another humiliation came when Walton, determined never to have children, forced his wife to have a backstreet abortion. She rationalised these setbacks, telling herself and friends that all men love beauty, and that his horror of children was because he needed the space for his work.

For all his fame and his moneyed acquaintances Walton's own income – around £3,000 a year – was not enough to sustain his London lifestyle, and he and Susana decided to move to Italy. It was now that she came into her own.

These days the splendour of La Mortella, Lady Walton's internationally renowned garden on Ischia, stands in marked contrast to the Waltons' introduction to the island where they were to spend the rest of their lives. After roaring down from London in Walton's Bentley, Susana had to drive it up two wobbly planks on to the deck of the boat that was to take them across (the captain moved aside two decrepit cows – the island's supply of fresh meat – to make room). Then the local police decided the Waltons didn't have the correct papers and told her to drive it off again. She responded that she was having none of it and ordered the captain to cast anchor. The boat then limped between the German mines that still littered the Bay of Naples – sitting so low in the water that Walton considered putting a cork in the Bentley's exhaust pipe.

The rented house they occupied was a far cry from the comfort left behind, as Rod Gilchrist related in an Independent profile in 2006: 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 bribed local fishermen for their supply.

The land they bought was basically a rocky volcanic outcrop; their friend Lawrence Olivier – for whose three Shakespeare films, Henry V, Hamlet and Richard III, Walton had written the music – tried to talk them out of it. Undeterred, they hired the architect Russell Page to design their garden even before they considered the house. The pattern of their lives was soon established: Walton sat indoors and composed, and Susana put her back, literally, into the garden, planting, moving rocks and rubble, shaping it over the years into one of the wonders of the horticultural world.

Here they held court: Olivier and Vivien Leigh visited, Callas called, as did Chaplin. Walton found composition increasingly difficult, while his status back in Britain grew. At the Festival Hall concert to mark his 80th birthday in 1982, with Walton and his wife sitting in the Royal Box, the audience rose to pay tribute – the atmosphere was one of those special occasions when you can sense the nation giving thanks.

In 2004 La Mortella (the name means "myrtle") was voted "Il Parco più bello d'Italia". Every year it attracts an increasing number of visitors – some 70,000 in 2007 – who come to admire the profusion of plants and spectacular setting Gilchrist outlined:

"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."

The garden expanded over previously uncultivated areas, with Lady Walton's resolve apparently undimmed by severe arthritis. A recent transformation arose from her decision that La Mortella should be accessible to visitors in wheelchairs – a major challenge for a site ranged up a mountainside but one now substantially met.

The steely resolve she showed in transforming La Mortella was also required in her personal life: she tolerated Walton's philandering up to a point but would put her foot down when she had to – but she also knew that, a sometimes reluctant creator, he needed her support and understanding. After his death in 1983 she devoted herself to maintaining his memory through the downturn in fashion that often follows on a composer's demise, setting up the Fondazione William Walton e La Mortella.

Under her very active guidance, the Fondazione opened a museum and concert hall and, most recently, the Greek Theatre, an amphitheatre for open-air performances. Thus La Mortella is now not only a garden but also an important concert venue and base for musical education. Her two books, unsurprisingly, deal with her two loves: Behind the Façade (1989) was a candid account of life with her husband; La Mortella—an Italian Garden Paradise (2002) bore a foreword from the Prince of Wales, patron of the William Walton Trust.

In 2002 official recognition of her efforts came from both her adopted countries: she was made an MBE and a Grande Ufficiale della Repubblica Italiana. She had been awarded an Honorary Doctorate in Music from the University of Nottingham the previous year.

Susana Valeria Rosa Maria Gil Passo, gardener: born Buenos Aires 30 August 1926; married 1948 William Walton; died La Mortella, Ischia, Italy 21 March 2010.