Looking at the pictures in this month’s Country Life magazine of David and Victoria Beckham’s Cotswold country estate, it’s hard to believe that this is the same couple who wore purple and sat on gold thrones at their wedding in 1999.

But Posh and Becks, now Sir David and Lady Beckham, have become properly, indisputably posh. Victoria is a well-respected designer, while David trades beekeeping tips with King Charles.

Their garden, which is David’s pride and joy, is also achingly, impeccably on-trend. Everything from the planting choices to the plant supports, the water features and the way it is organically managed, speaks of the sort of refined sensibility which would surely have won the approval of famous gardening snobs such as Vita Sackville West, who created the legendary garden at Sissinghurst in Kent.

Of course, the Beckhams have far more money to lavish on their plot than the rest of us, but looking at their garden offers useful tips on what is the height of fashion in the world of horticulture, and what is best left on the compost heap.

In: Greenhouse for entertaining

Out: An outdoor kitchen

If there’s one thing I really, really want from the Beckhams’ garden, it’s their graphite grey greenhouse. What a thing of beauty!

With its black and white chequerboard floor, weathered wooden shelves and a table big enough to accommodate 20 people, this is the dream space. It was made by upmarket company Alitex, whose smallest conservatories cost around £20,000. Having a glamorous greenhouse-cum-dining room is in a different league from having an outdoor kitchen; no matter the weather, you can host parties in the middle of the garden (it helps that the Beckham greenhouse has a woodburning stove). Yes, you need a big budget, but every posh gardener will now be lusting after one.

In: Rills

Out: Fountains

For those who have the space, a water feature can be a wonderful centrepiece, and nothing says ‘grandeur’ like a fountain. The problem is, fountains almost always look ridiculous in all but the very grandest British gardens.

The answer is to install a rill. For the uninitiated this is a narrow, shallow channel of gently flowing water which looks something like a mini canal. A rill is a lovely way to bring water into the garden and its linear design creates a strong focal point.

Rills were a key feature of Islamic gardens, where they typically represented the four rivers of paradise, and have become a very fashionable water feature. Do the Beckhams have a rill tucked away somewhere? It wouldn’t be a surprise if they did.

In: Natural swimming pools

Out: Swimming pools

Swimming pools, with all the chemicals that are needed to keep them clean, are something of an environmental menace. What’s more, for over half the year they have to be covered. Increasingly, posh gardeners are installing natural swimming ponds, which have long been popular in northern Europe.

The idea is to have a natural looking body of water with a shallow shelf stocked with oxygenating plants, which keep the water clean and free of algae.

A mechanical pump circulates the water and a barrier separates the shallow shelf from the deeper water, so that the soil doesn’t spill over into the area used for swimming. The edges of the pond are planted with ornamental grasses and waterlilies, so you swim surrounded by plants, with dragonflies and the occasional bird skimming in and out of the water.

At their Oxfordshire estate the Beckhams have hedged their bets with both a swimming pool and a magnificent lake, edged with rushes and lavender, with a wooden walkway to a central island. You can’t imagine Victoria swimming among the rushes, but on warm summer evenings it would be a blissful place for a dip.

In: Wildflower lawns

Out: Fake lawns

Probably the worst gardening trend of the past 50 years is fake grass, which has spread like a plasticky plague. Not only does it have a high carbon footprint, it’s a disaster for the environment.

Whereas a lawn supports worms and a host of insects, fake grass creates a biodiversity wasteland. To be really fashionable, though, it’s not enough to have a nicely mown lawn like the Beckhams.

The trend is increasingly towards wildflower lawns, where the grass is dotted with colourful wild flowers like corncockles, poppies and clover, which is more difficult than it looks. Seeds will probably be eaten by birds and grass can smother the plants.

A simpler solution is to let the grass do its own thing for ‘no mow May’. If you can’t cope with a very messy lawn for four weeks, then the compromise is to leave a few unmown patches in less visible areas of your garden throughout the summer.

Even small pockets of long grass are very helpful to bees, butterflies and other insects.

In: New English roses

Out: Hybrid teas and floribundas

What a delightful idea for Harper Beckham to get a white rose named after her father for his 50th birthday present. No wonder she was excited about it, telling him in the run-up to the big day: ‘Daddy, I’ve bought you something money can’t buy.’ What’s more, Harper was on trend in choosing a rose bred by David Austin. Since the late 1960s this Shropshire nursery has been producing gloriously sumptuous and fragrant roses, technically called New English Roses but known to all as ‘David Austin roses’.

These roses are sold all over the world and have the shape and heady perfume of an old-fashioned rose, but will flower again after the first burst of blooms in June. They are also more disease-resistant than 18th or 19th century roses, which by the way are also still very much in fashion amongst rose aficionados.

All of which means that modern hybrid tea and floribunda roses, with their large, single blooms carried on stiff stems, have fallen right out of fashion. If you want your garden to look posh, a mixture of David Austin roses and historic roses such as ‘Mme Isaac Pereire’ and ‘Buff Beauty’ is the way to go.

In: Lavender

Out: Begonias and busy lizzies

There’s one plant that crops up repeatedly in the Beckhams’ garden: lavender. It’s around the swimming pool, and a sinuous ribbon of lavender also surrounds the ornamental lake.

There are over 400 varieties, and David has chosen one of the very best: ‘Hidcote’, which has rich purple-blue flowers, smells fantastic, flowers over a long period, and will be much appreciated as a source of nectar and pollen by David’s beloved bees.

Lavender is timelessly elegant. It works well as an edging plant, as a bedding plant (mingled with roses, peonies and foxgloves, for instance) and in containers and window boxes.

And because it ticks all the right boxes for insects, it’s seen as a much more upmarket choice than the more traditional begonias, petunias and busy lizzies.

Posh gardeners regard bright, cheap and easy-to-grow bedding plants as a rather vulgar, cheap fix, like buying a £5 T-shirt from Primark. Not only are the colours on the gaudy side, but bedding plants are usually bred to have large double flowers which have little or no accessible nectar, so they aren’t beneficial to insects.

In making lavender their signature plant, the Beckhams have opted for the Prada of the plant world.

In: Cotswold Legbar chickens

Out: Silkies

David Beckham loves his chickens, and has chosen one of the poshest heritage breeds, the Cotswold Legbar, which lays elegant pastel blue eggs with a deep yellow yolk. Keeping chickens is a very posh thing to do. It probably won’t save you any money on your food bill, but it can be an immensely satisfying hobby and will give you fresh, high-quality eggs. One breed to avoid is the Silkie. Despite its adorable fluffy plumage, it’s a poor egg producer, is not hardy in cold, wet weather, and is susceptible to disease.

In: Woven willow plant supports

Out: Plastic supports

Few things scream ‘posh’ in a garden more than woven willow, whether used for hedging, fences or as a plant support. The great advantage of woven willow is that it’s an attractive feature in itself, whereas plastic plant supports, even those that are a discreet green, are something of an eyesore until the plants grow big enough to conceal them.

The Beckhams’ plant supports are made by Somerset craftsman Jay Davey, whose work has also been commissioned by Highgrove House and Clarence House. He has created large willow cloches for David’s peonies and roses and made supports for his vegetables and sweet peas, as well as building a few willow arches for the Beckham estate. Yes, plastic plant supports are more affordable, but if you’ve got the money, natural supports add class to any garden.

In: Saunas

Out: Hot tubs

How do you feel about hot tubs? Are they an asset to a garden, or a sleazy eyesore fit only for the contestants of Love Island?

There are now an estimated 330,000 fixed hot tubs in the UK, with a further 800,000 inflatable ones knocking about people’s garages.

Posh gardeners would never dream of installing a hot tub, but they are increasingly keen on saunas. Even Gardens Illustrated, the magazine that’s a bible of what’s tasteful in the garden, is singing their praises, and sales of mobile wood-fired saunas are soaring.

The Beckhams have a sauna in their garden, a small black dome which houses an Iglucraft design, made in Estonia (prices for a double sauna start at £17,000). They also have a hot tub, but since it’s wood-fired it’s definitely a cut above most.

In: Espaliered fruit trees

Out: Trees in pots

Few of us have room for an orchard, or even the space to plant a cherry tree outside our partner’s study window so that they can enjoy the blossom in spring, as David did for Victoria. Yet growing fruit trees in a small garden isn’t impossible. Miniature fruit trees have been around for decades – you can grow apples, pears, plums, even mulberries in a container. The problem is, the taste of the fruit is consistently disappointing.

A far better idea is to plant espaliered fruit. This is an ancient method of training fruit trees flat against a fence, wall or trellis, then pruning and tying in the branches to create a decorative pattern. This is what David has done with his plum and pear trees. It doesn’t take up much space, it looks spectacular, and picking plums to make jam (one of David’s favourite hobbies, apparently) is all the easier. You can even fit an espaliered fruit tree into a front garden, too, as long as you have a fence.