The late Rosemary Verey made her garden one of the most famous in the world during the 1980s and 1990s. Its appealing floral vistas, diminutive ornamental potager and woven knot-garden were on a scale that many gardeners could relate to, and the international reputation she earned through her gardening books drew visitors from all over the world. Indeed, one of the memorable occasions when I toured the garden of Barnsley House with Mrs Verey was when I was commissioned to write an article about it for a Japanese magazine, as the garden’s renown had spread to the Land of the Rising Sun (which, in return, obliged with coachloads of visitors).

Mrs Verey, who for many years contributed a column to Country Life, admitted to receiving about 25,000 horticultural pilgrims each year. They admired exuberant beds burgeoning with a non-stop show of annual and perennial flowers through spring and summer, but the look was a laissez-faire country style, underpinned by a tireless regime of dead-heading through the seasons, and a wealth of evergreen shrubs that continued the show magnificently through each winter. (Mrs Verey described her style as ‘combining a formal structure with luxuriant planting’.) When Barnsley House came up for sale in 2002, a year after Mrs Verey’s death, naturally there was much talk about what might happen to the garden.

As it turns out, the property has found entirely sympathetic owners in Tim Haigh and Rupert Pendered, who for some years had already made a name for themselves, catering-wise, at The Village Pub, just across the street. They carefully turned Mrs Verey’s elegant, 17th-century stone house into an ultra-chic boutique hotel and restaurant that would appeal to a new generation of Cotswolds visitors, but have kept faith with Mrs Verey’s garden to a remarkable degree, while adding exciting new areas to the periphery. One of the most recent innovations is a bold, Minimalist garden designed by Stephen Woodhams, ranged around a new spa in the grounds, accommodating a luxurious plunge pool with therapeutic showers.

The impressive spa building (with a womb-like cavern of underground treatment rooms) features dry-stone walling in its interior, echoing the Cotswolds vernacular. This is repeated outside in a dramatically curled stone wall, stitched with houseleeks and other crevice dwellers, beside a flagstoned terrace and soothing water rill. Unlike other, more eclectic parts of the garden, the spa is a contemplative area of calm greenery, trickling water and pale stone, reached via a serpentine woodland walk. (Its pared-down style is also evident in a couple of private guest courtyards in the grounds and a new garden woven through the new ‘stable block’ rooms.)

Mrs Verey modelled her famous potager kitchen garden on a design in William Lawson’s Country Housewife’s Garden (published 1618). ‘His advice was never to have your beds more than five feet wide so the “weeder women” need not tread on them,’ she wrote, when the garden was newly laid out. ‘We have found this very good counsel.’ She would be amazed, and, I think, thrilled to see the extensive new hotel kitchen garden that has been made in the former paddock adjoining the potager.

Here, the existing corrugated land pattern of an ancient ridge-and-furrow system has been creatively put to use for a series of highly productive herb, vegetable and salad beds maintained organically on a rotational system. The kitchen garden is the domain of deputy head gardener Mark Burge, who presently cultivates seven substantial beds that follow the form of the ridges. Their productivity and vigour is astounding, as the historic curves of the land have been found to enhance both the available light and the drainage in the heavy soil. One area, devoted to garlic, includes the varieties Lautrec, Iberia, Solent White and Elephant garlic.

In a bed of brassicas, I found Black Tuscan kale, purple sprouting broccoli and Romanesco cauliflowers. The salad beds are particularly beautiful, with an array of lettuces used creatively in the hotel’s kitchen; they include Marvel of Four Seasons (which is, as its name suggests, an all-year-round lettuce); the ever-popular, sweet-flavoured Little Gem, Rubine (a red Iceberg type), and sharp-flavoured Catalogna. The permanent herb bed is a traditional assembly of shrubby sages, rosemary, marjorams and floaty fennel.

Elsewhere, you will find masses of flat-leaved parsley and dill. Even the onions at Barnsley House are out of the ordinary, including the light yellow, very flat Borettana; flattish, red Di Genova; and the bunching red onion, Rossa Lunga. If ever there was somewhere to provoke kitchen-garden envy, it’s here, on the ridges and furrows and also in the nearby tomato tunnel, an aromatic polythene hothouse of Black Russian, super-sized Coeur de Boeuf and Cuostralee, and diminutive Black Cherry, Apero, Gardener’s Delight and Sungold. Another tunnel protects early crops of lettuces and pea tops, dill and several mustards Giant Red, Green in Snow and Golden Streaks.

The gardeners at Barnsley House (under the aegis of head gardener Richard Gatenby, who also worked for Mrs Verey) don’t expect guests to rush to inspect the range of compost heaps (which are impressive). But if you take an interest, they will also tell you with pride that the horse manure used on the gardens is locally sourced from ex-champion jockey Willie Carson’s stud just up the lane. Yes, high standards have been maintained at Barnsley House, even down to the muck on the flowerbeds. Barnsley House, Barnsley, Cirencester, Gloucestershire (01285 740000; www.barnsleyhouse.com).

The gardens are only open to guests of the hotel, but there are usually several public open days each year for the National Gardens Scheme (the next one will be August 21, 11am to 5pm). Seeds of unusual vegetables in the kitchen garden are sourced from Simpson’s Seeds (www.simpsonsseeds.co.uk), Franchi Sementi (www.seedsofitaly.com) and Chiltern Seeds (www.chilternseeds.co.uk) Photographs: Andrew Lawson.