Thousands of thirtysomethings are shunning the pub on Bank Holiday weekends and going instead to Britain's 2,500 garden centres to fill their trolleys with shrubs, plants and potting compost.
The numbers of gardening magazines and television programmes are fast overtaking cooking and interior decorating as the latest consumer passion. Last year, Britons spent pounds 3bn on their gardens compared with pounds 2.3bn two years ago.
"There's a new interest in gardening from the young, professional urban classes, people who would have thought of gardening as totally unfashionable 10 years ago," said Tim Richardson, the editor of New Eden, a gardening monthly to be launched on 15 April.
His findings were certainly borne out by the hordes of young couples at the Alexandra Palace Garden Centre in north London yesterday. Simon Eade, the manager, said the good weather was making people think about their gardens. "We are busy now and Monday will be mad," he said.
A three-acre garden centre can expect at least 1,000 customers on a sunny day, and it could regularly take more than pounds 20,000. "Centres of this size can make at least pounds 2m a year and some will make up to pounds 3.5m," said Mr Eade.
Adge Gittins, 30, has just bought his first house with a garden, and was busy hunting for trellis and plants. "I don't come that often - well, I was here last week - I'm getting quite into gardening," he said.
Beric Livingstone and Simon Ash had come to completely kit out their garden. "We may well spend more than pounds 300, there's so much here," said Mr Livingstone.
Ariane Gentil had come for a look around with her partner, Remi Adewusi, a recent convert. "It is wonderful to plant something and watch it grow and it becomes addictive," he said. Ms Gentil said she had subconsciously started to budget for plants out of her monthly income. "I say that I won't spend more than pounds 30 a month, but sometimes I will just blow pounds 100 in one go and then try not to come back again for a few weeks," she said.
Twenty minutes later the couple were staggering out to their car under the weight of several pots and at least one small tree.
Everyone admitted to watching gardening programmes avidly, particularly Ground Force, with Alan Titchmarsh and the famously bra-less Charlie Dimmock. But times have changed. Ten years ago, Ms Dimmock would have been the main interest; now it is Mr Titchmarsh, and even he plays second fiddle to the plants.
There are now up to six gardening programmes a week, and magazines such as the functional BBC Gardeners' World are flourishing.
The national obsession with producing flowers and plants is reflected in the latest figures from Bookwatch, which lists the highest-selling living author, for both fiction and non-fiction, as Dr D G Hessayon. Dr Hessayon's The Garden Expert and The House Plant Expert have sold more than 17 million copies between them, outstripping the collected works of John Grisham, Danielle Steel and even Delia Smith.
"You don't just have to stick a lawn down and surround it with roses, you can stylise and personalise it," says Tony Sutton, manager of Alliston's nursery on the King's Road in Chelsea. "A much more contemporary look is in, people are becoming more theatrical."