The odd thing about sex in the garden, given that it started in a garden, is that we make so little of it today despite the erotically charged specimens we cultivate – such as the rampant Arisaema. Sex used to be a celebrated part of our landscape, as Sir Francis Dashwood of Hellfire fame showed in the 18th century when he created the sexiest garden in Britain and gave us a glimpse of what today’s gardens are missing. Action.

His Venus garden, at West Wycombe in Buckinghamshire, is designed to suggest the goddess’s naked form. Venus’ splayed legs are etched into the ground in the shape of paths running either side of her grassy mount. And her mount is pierced by an oval slit opening into a damp grotto. An erect flint pillar once stood in front of the opening and may have been topped by a statue of Mercury, mercury being the contemporary “cure” for syphilis.

Venus was the ideal sexy icon for any garden: the beautiful, sensual goddess of love and gardens. Images of Keira Knightley would be a near equivalent today although I doubt her agent would allow the kind of exposure that Venus was given by Sir Francis and others.

His Venus garden may have been at the extreme end of acceptability but raunchy landscaping was not unusual, and “pleasuring sophas”, dark grottos and erotic paintings and statues were part of any self-respecting landscape garden of the time.

These stimulating scenes, coupled with lack of privacy in the main house, added to the allure of the pavilions, arbours, grottos and temples dotted around the grounds. A bracing walk or ride would carry you away from the hubbub of the house. And the riding could then carry on inside these lovely garden buildings.

The largest place for this kind of garden activity can be found just outside Bedford at Wrest Park. Thomas Archer’s massive pavilion has a series of small doors off the atrium, each opening on to a narrow staircase up to a small room, just large enough for a couple.

Lovers in all these gardens were given inspiration and encouragement by statues and features that conjured up sexy stories about gods and goddesses. At Rousham, near Oxford, Venus stands in a clearing, above water spouts, while Pan and a faun leer at the naked goddess through the undergrowth. Down the road at Stowe, a golden Venus stands in her own rotunda near her temple originally decorated with erotic wall paintings. A spurting obelisk gave the scene gender balance.

By 1819 Sir Francis’s erotic creation had been destroyed along with that era of educated sensuality. The 19th century had brought down its curtain of respectability. The temples and pavilions dwindled into picturesque ruins while smart new Victorian gardens acquired summer houses and croquet lawns.

The 20th century was little better, apart from the odd moment of erotic recall when a designer smuggled a sex garden into the Chelsea Flower Show, and the landscaper Sir Geoffrey Jellicoe told his bulldozer driver to sculpt a hill “like the curves of a woman”. Back at West Wycombe, Sir Francis’s outrageous celebration of Venus reappeared when his garden was restored and opened with an “undress rehearsal” in which a naked woman emerged to recreate The Birth of Venus.

Today I can think of a couple of sexy, but very private, grottos that have been made in the past few years. But most of us are so busy larding our real estate value by embellishing our backyards with lighting and water features that we lose sight of a garden’s hidden charms. Gardens are, after all, more than “outdoor rooms” and areas to dump the washing, the bins and the kids. They are places that should be able to inspire more than a longing to grow bigger marrows or brighter Verbena bonariensis.

As Tim Smit, the Eden Project’s creator, said, if you can’t make love in a garden you should tarmac it over. Equally, the Beatles’ question, Why Don’t We Do It in the Road? always makes me feel like shouting the answer, “Because Doing It In The Garden Is Better”. This could be a sentiment I owe to Hellfire Sir Francis – we are distantly related – but I think that, deep down, we British are all far more sensual than we pretend. Maybe it’s time to acknowledge this, along with the erotic potential of our garden sheds and spurting water features.

Jane Owen is appearing in The Garden Revolution , a Time Team special, on August 27 at 9pm on Channel 4 to talk about erotic gardens with Tony Robinson. www.janeowen.co.uk

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