Just the tonic for British gin

Native juniper berries, which give mother's ruin its unique flavour, are being saved from extinction. Michael McCarthy raises a glass to the Ice Age evergreen that put the UK distillery industry in high spirits

Gin drinkers, raise your glasses – the juniper, with its fragrant fruit, has been revived in Britain. Juniper berries are the essential flavouring ingredient in that clear spirit, whose evil reputation once gave it the name of mother's ruin, but which is now seen more benignly as the interesting part of a gin and tonic.

But the bushes that bear the aromatic berries have been disappearing across Britain, and in southern England have been in danger of extinction in the wild.

Now, however, the wild flower conservation charity Plantlife has just completed the first phase of a major project to revive the fortunes of Juniperus communis, with 300 juniper seedlings growing at nine sites where existing juniper bushes were old and incapable of reproducing, a conservation success that has never before been achieved on this scale.

Juniper is a fascinating plant in that it is one of only three native British conifers – the others are the yew and the scots pine – and it was one of the first trees to colonise Britain after the last Ice Age.

Juniper numbers have fluctuated but on the whole declined over a long period, with many southern English counties having lost 60 to 70 per cent of their populations. Without action, the shrub (it's generally shrubby-sized) was facing extinction here in the next 50 years, so in early 2010, Plantlife launched a conservation project and survey to help to save the species in the English lowlands. It has involved trialling new techniques to build up the most important populations across the chalk and limestone country of lowland southern England.

"More than 30 project sites were chosen for a range of conservation measures, including large-scale habitat management, experimental seedling shelters and – where colonies had all but died out – the propagation of cuttings for later replanting," said Tim Wilkins, Plantlife's species recovery co-ordinator, who led the project.

"Our Great Juniper Hunt survey in 2010-11 showed that many populations of juniper were shrinking as bushes died of old age, with nearly a quarter of sites supporting just one bush, and 85 per cent of sites surveyed containing no seedlings up to five years old.

"To get the next generation of juniper, you need good numbers of both male and female bushes at each site, plenty of viable seed, and the right conditions for germination and growth of seedlings, free of hungry rabbits and grazing stock."

The word "gin" derives from either genièvre or jenever – the French and Dutch words for "juniper". The berries are also used in cooking, particularly to flavour game dishes.

In the 19th century, when a law was introduced outlawing unlicensed whisky stills, juniper was harvested for fuel for this illicit trade as it burns with an almost invisible smoke.

Juniper has also long been used for its medicinal qualities. During the 1918 Spanish flu epidemic, hospitals experimented with spraying vaporised oils into the atmosphere of flu wards in an attempt to prevent airborne infection spreading, and juniper was one of those found to be particularly effective.

"There is no single cause for juniper decline but loss of seedling habitat, through under-grazing and the development of dense grassland and scrub, seems to be the most widespread," Tim Wilkins said. "Some colonies were also affected by a shortage of viable seed, or were overrun with rabbits eating any emerging seedlings."

He added: "The loss of juniper would have represented more than the loss of a single species: it supports more than 40 species of insect and fungus that cannot survive without it. The special conditions thought to be necessary for juniper seeds to germinate are also beneficial to a host of other wild plants, many of which are also under threat."

Best of British? Where UK distillers source juniper berries

The juniper bush may be undergoing a revival in England but leading distilleries are still reliant on foreign imports to meet the requirements of a booming gin industry.

Beefeater Gin

Desmond Payne, master distiller: "The most important day in our calendar is what we call 'The Big Juniper Sniff'. It's when we make our annual assessment of this year's juniper crop and create a blend that maintains consistent flavour year after year.

"There are juniper berries all over the place – I've found them growing in Chicago and Scotland – but most of the juniper for the gin trade comes from Italy. It's not cultivated anywhere, apart from the odd garden centre; instead it grows wild and people forage for berries in the same way that they search for truffles.

"Most of the samples are Italian. The hot summers in Umbria develop the oils in the berry and in colder climates it's harder to get the high oil content that puts the flavour into the spirit for gin.

"It would be lovely to use English juniper but it would have to be fit for purpose."

Sipsmiths Gin

Chris Garden, head distiller: "The company has trialled berries from all over – we like Macedonian ones best. By law juniper must be the dominating flavour in gin and the differences between each batch comes down to the details; two little pieces of peel might have slightly different levels of oil and affect the taste.

"We got a batch of juniper berries from Kew Gardens but they just weren't of good enough quality and they weren't mature enough. I don't think the climate was right."

Hendrick's Gin

Duncan McRae, brand ambassador: "There's a very small part of a juniper berry that we actually want: the seeds that contain the essential oils and give it the fresh smell.

"We buy once a year at the end of the growing season and merchants send us samples from around the world that are extensively tested.

"The great thing about juniper is that it takes two years for a berry to ripen properly – so you might have three harvests on the same tree.

"A lot of the berries are still gathered by hand in the traditional manner: people beat the shrubs with a stick until the ripe berries fall to the ground and can be collected. It's very labour intensive."

James Waterson

Gin: Spirit of the times

Gin is a drink with a decidedly disreputable past. At the height of its notoriety in the middle of the 18th century, it was considered responsible for degrading much of society, and became known as "Mother's Ruin" – an image reflected in Hogarth's famous 1751 engraving Gin Lane, where a gin-sodden mother is depicted as being so incapable that she is dropping her baby.

The flavouring of grain spirit with juniper had been invented in the Netherlands a century before, originally with a medicinal purpose in mind; but by Hogarth's day it had become the cheapest drink for the masses in Georgian London.

It was in the late-19th century that gin at last became respectable – a transformation that happened for two reasons. The Royal Navy adopted pink gin (gin with angostura bitters) as its preferred drink. And around the same time officials in the British colonies created gin and tonic – a way of livening up tonic water, which contained quinine and was taken to ward off malaria.