dTrevor Wood’s grandmother could not have guessed the seed she was sowing as she busied herself potting plants in her greenhouse. Every Sunday afternoon, when his parents were working in their shop, the young Trevor would go around to see her. When it came to plants, his grandma could be fastidious but he always looked forward to watching her at work.

As the head gardener at Blenheim Palace, where he has worked for more than 25 years, his enthusiasm for plants has only grown. And that’s just as well, given the challenge that awaits him every morning when he pulls on his boots.

For those of us who grumble at the prospect of a few hours’ weeding over a Bank Holiday weekend, it is difficult to even begin to contemplate the scale of the task facing Mr Wood and his wife Hilary each day.

They are responsible for looking after 98 acres of gardens at Blenheim, meeting the exacting standards expected by hundreds of thousands of visitors and of course his boss, the 11th Duke of Marlborough.

The duke’s gardens are all encompassing, with formal gardens, water terraces, pleasure gardens, the arboretum, a rose garden and the second largest symbolic hedge maze in the world. Yet Mr and Mrs Wood somehow manage to maintain all these with a trimmed-down team of just ten gardeners, whose ranks include their 22-year-old son, Matthew.

As visitors quickly learn at Blenheim, the overriding legacy is Capability Brown’s, whose setting for Sir John Vanbrugh’s palace secured Blenheim its World Heritage status.

Down the years the Woods have been more than happy to see credit continuing to go Capability’s way for the magnificence of the landscape, even if it was devised in the 1760s.

But for this year at least, the Woods are to enjoy deserved recognition for their work over a quarter of a century, with Blenheim Palace winning the 2008 Garden of the Year award, sponsored by the Historic Houses Association and Christie’s.

The national award, celebrating its own 25th anniversary this year, is designed to recognise the importance of gardens with outstanding horticultural and public appeal, either in their own right or as a setting for an historic house.

It is the first time Blenheim has won the award, which in previous years has gone to Hever Castle in Kent, Cottesbrooke Hall in Northamptonshire and Sudeley Castle in Gloucestershire While the duke said the award recognised “the vision and enthusiasm of my illustrious ancestors”, he used the unveiling of the award last Thursday to pay his own tribute to his team of gardeners. “All credit must go to the gardening staff who look after the gardens in immaculate fashion,” he told his guests, with his wife, the new Duchess of Marlborough, Lily Mahtani, standing by his side.

When one of the speakers, Charlie Cator, chairman of Christie’s, joked about the use of spirit levels in order to ensure hedges had an even flatness, the head gardener could not hold back a smile.

For, sure enough, spirit levels are used during trimming to maintain the hedges in the Italian Garden, where the presentation was taking place, with guests including Viscount Linley.

This garden was created by the 9th Duke of Marlborough on the advice of his French architect, Achille Duchene, with an earlier scheme of carpet bedding replaced by formal symmetrical scrollwork parterres in box and yew, to leave today’s gardeners with the unenviable task of keeping the numerous box-hedges in pristine condition.

“Cutting hedges is the hardest part,” Mr Wood admitted. “Using heavy machinery for eight hours is back-breaking work. I still get involved and we now wear corsets for support.”

Running the gardens, he says, is like a military operation, with everything carefully planned. The three-acre south lawn has to be cut twice a week, rain or shine. The grass verges are cut weekly, and plants deadheaded daily in some cases, to keep them in good condition and prolong flowering.

The duke’s continuing interest in his gardens must be something of a double-edged sword, I suggest. Life would surely be a good deal easier if the boss didn’t know his Azara Serrata from his Iris Confusa.

“The duke has an eye for detail. He certainly has an eye for a straight line,” said Mr Wood, aged 58. “It is important to him that everything looks right.”

Particular attention is always paid to the four Valencia orange trees in tubs, which produce fruit for the duke’s breakfast marmalade. It will not go unnoticed if the fruit is left on the tree for too long.

The duke’s determination to build on Blenheim’s horticultural legacy has certainly added to the workload of his gardeners. While planning a suitable project to mark the tercentenary of the Battle of Blenheim, he hit on the idea of bringing his father’s private garden back to life, preserving the original layout but introducing new features.

“It was created four years after he had opened the house to the public in 1950,” explained the duke. “My father designed this haven as a romantic English garden. It had become completely overgrown and almost forgotten when we undertook its restoration. Trevor Wood replanted it and established new paths and water features in record time for the official opening in May 2004. It was renamed the Secret Garden and it has matured delightfully.”

Twenty years before, he had established a new hedge maze, with elements of military symbolism celebrating the career of his ancestor John Churchill and the victory for which this great house was his reward. It was constructed within the walls of the old kitchen garden that had once been planted with espaliered fruit trees and neat rows of vegetables, stocked by the royal gardener, Henry Wise.

As for the Italian Garden, the duke told his guests that he could only take credit for the introduction of red gravel between the box hedges.

But he certainly deserves lasting thanks for securing the services of Mr Wood in 1981, who was initially taken on as foreman of the gardens. Mr Wood had previously worked at a nursery in Hadlow before becoming the under gardener at Leeds Castle, where he met his wife. The famous castle in Kent certainly provided the ideal training for his future role in Woodstock.

“My father had a business running shops. But my parents and grandparents were very keen gardeners,” said Mr Wood. “It was my grandmother who taught me how to grow plants. If I planted something incorrectly, she would tell me. She was quite strict.”

The lessons were well learnt.

“Everything you see here was grown from cuttings. Every September we take the cuts and grow them through the winter. It is a 24-hour job, but I enjoy it. I can still step back and look at beds and everything we have done. I will retire in eight years but I want to spend the rest of my working life here.”

The couple live in the palace grounds in The Bothy, a 19th-century house, where, yes, they do have their own garden to maintain.

“We wouldn’t want you to see that at the moment,” said Mrs Wood, although I suspect it would be anything but overgrown, despite the fact they are never really away from their majestic but demanding workplace. “It is not really a job. It is rather more a way of life,” said Mrs Wood, recalling that she has seen her husband going off to work for half a morning even on Christmas Day. “There are always plants to take care of and, of course, 98 acres of gardens. There are always jobs to be done.

“The terrible danger is that you end up going around looking for the bad points, thinking, ‘how untidy is that?’, while other people are commenting on the magnificence of it all.”

But surely she must sometimes wake with an aching back never wanting to push another wheelbarrow, pick up a spade or bend over a flowerbed for the rest of her life?

She shakes her head: “If you wake up feeling, ‘oh God, another day’, that’s the time to move on. It would mean that your passion had gone for the place. People are always amazed that there is not an army of 50 or so people looking after it all.”

The automatic irrigation system spares the team from having to spend hours watering every border and urn by hand. But the huge grass-cutting operation must always go on whatever the weather conditions.

“The thing I hate most is cutting the grass in rain — everything getting bunged up,” she said.

The Secret Garden is certainly not viewed as an additional burden and has certainly captured her imagination.

“I think it is a place people can really relate to. People go along and get ideas for their own gardens.”

The Secret Garden no doubt played its part in giving Blenheim a very public boost, by persuading the Friends of Historic Houses Association to name Blenheim the winner for “the great diversity of scale and type” of its gardens and its ability to offer every visitor “a special experience”.

As for the never-ending military operation required to achieve it all, well suffice to say it is surely worthy of the first duke.