After a long, hard winter, Chelsea bursts into life

Between them, John Hillier and Ricky Dorlay can boast 96 years of Chelsea Flower Shows, and they both agree there hasn't been a winter like it for at least a couple of decades. "It's definitely the most difficult one for 20 years," says Ricky, with one eye on the positioning of a tree on the Hillier Nurseries stand.

It's the Thursday before the show opens, and it's been a nail-biting time for the Hillier team, who are hoping to win their 65th consecutive gold medal at Chelsea. Ricky's been at every show for 45 years – "though of course when I started I was just a young lad with a hosepipe, being told what to do by Harold Hillier" – and everything is three weeks behind.

The problem hasn't just been the frigid temperatures of the long winter but also the low levels of light. "Last week, we were -3C at nights," says Ricky. "That's fine for established plants but it's a much more serious thing for young stock. The rhododendrons and the cornus have been all right, but bringing on the roses has been a real problem."

John Hillier thinks the last winter that was as bad as this – for Hillier's, anyway – was 1954 ("the year I went on National Service") when the company lost their entire stock of azaleas overnight in a severe frost.

The list of problems facing Chelsea exhibitors in this particular year, however, reads like the prelude to an apocalypse – endless winter, recession, volcanic eruptions, even civil unrest. Yet the growers and designers are philosophical, smiling as they tell their tales of disasters overcome. The wartime phrase "Keep Calm and Carry On", recycled for an era of financial crisis, might have been coined especially for horticulturalists. Gardeners are eternal optimists – they have to be. For professionals and keen amateurs alike, the loss of a plant is often determinedly seen as an opportunity to do something different, rather than rage at the unfairness of life.

David Rhodes of the begonia specialists Rhodes and Rockcliffe scoffs when I suggest that his hothouse-nurtured exhibits might not have suffered in the long winter. The flowering varieties have been very badly affected by the low light levels and he has had to leave some of his prized specimens at home this year because they didn't develop buds in time. "It's not all doom and gloom, though," he says, "because instead we've brought two varieties of begonia that have never been shown at Chelsea before. – Kyoto and Wild Fury."

For Sue Hayward, designer of the Stephen Hawking Garden for motor neurone disease, replacements were not so easily found. Her concept is a brief history of plant evolution, beginning with ancient specimens such as gingko and taxodium, and ending with the Mediterranean plants we may all be growing in Britain if global warming continues.

When her gingko arrived, it had frost damage. Gingkos are not exactly common, and a frantic search began for a substitute. Did she ever worry that she might have trouble sourcing such a plant?

"To be honest," says Sue, ruefully, "I reckoned the trees were the least of my problems. I was more worried about my drystone wall. I had a team of specialist drystone builders coming down from Scotland, and they only just managed to get on the last flight before the volcanic ash closed the airport."

Designer Mark Gregory, creator of a teenage paradise with plunge pool and pizza oven for The Children's Society, has also been a victim of ash. In April, he was in Mauritius with his family on a pre-Chelsea break when the Icelandic volcano erupted.

"At first you think, oh great, let's have another couple of days in the sun, and another cocktail. But as time went on, you start to worry. We were due on site to start building on 5 May. Luckily I had my laptop with me, so I was able to work looking out on to the Indian Ocean."

Mark's jungly mix of stately rheums, spreading, lacy viburnum and acers hasn't been affected by the weather, but next door, on the Gaze Burvill stand, designer David Forestier-Walker admits to having lost six hours sleep the previous night - because of the heat.

Temperatures in the capital have been in the mid-20sC and are forecast to get hotter before the show opens on Tuesday. David is worried that his spring-fresh mix of alchemilla, forget-me-nots and dicentra, complementing the company's silk-smooth British-made oak furniture, will flop in the muggy warmth of a London heatwave. Mark Gregory, who is also the contractor on the Tourism Malaysia garden designed by ethnobotanist James Wong and David Cubero, is worried about the effects of the sun on the elegant cyatheas, a genus of tree fern.

James, the presenter of the television series Grow Your Own Drugs, shrugs off any concerns with a smile. "They'll be fine," he says. It's ironic that his garden contains the most exotic plants, yet he has had the least trouble with cold affecting his supplies. Most of the plants he has used, though native to Malaysia in a species form at least, are grown as houseplants in Europe. They have been shipped over in lorries from polytunnels in Holland, thus avoiding frost and ash problems in one go.

Nothing ever goes completely smoothly at Chelsea, however, and James shows me trolleys full of plants where the wrong variety of alocasia has been sent – "Black Magic" instead of "Black Velvet".

In the Great Pavilion, another South-east Asian team has not had so much luck. The exhibit by the Nong Nooch Tropical Botanical Garden in Thailand is taking shape under the supervision of owner Kampon Tansacha, but when I talk to them, they are still awaiting the arrival of a container-load of orchids, held up at Heathrow because of a glitch in the paperwork. Because of the political situation in Bangkok, where a curfew was put in place following the surrender of the Red Shirt protesters, it has been impossible to sort out the discrepancy.

They are already a day behind schedule, their flights having been held up by what co-ordinator Anders Lindstrom describes as "the supposed ash cloud". But, watching Kampon, whose attention never wavers from the meticulous pruning of a bamboo, I get the impression that it would take more than a volcano or civil unrest to stop him in his tracks.

The same aura of unstoppable force can be felt on the Winchester Growers stand, where the display of dahlias, in brilliant colours ranging from crimson through orange to apricot, glows like molten lava. Mary Payne and her team are determined to bring colour to Chelsea in what has been forecast to be a less floriferous year and they have certainly succeeded. Mary is intensely proud of the fact that her plants are British-grown, in Penzance. Out of fashion for many years but now enjoying a resurgence ("thanks to us," says Mary), dahlias normally bloom in late summer, so they have to be forced for a show as early as Chelsea.

Sean Atkinson, of Heucheraholics, based in the New Forest, has had no need of artificial light to bring colour to his Great Pavilion display. He's benefited from the cold winter, which has enhanced the coppery tones of his plants, favourites with gardeners because of their foliage colour range and tolerance of dry shade. "The colours have been fantastic this year," he says. "Heucheras like the cold and it's really made them glow."

But there is one problem that even the most sunny-natured grower finds it difficult to forgive. Just along from Sean's heucheras is a stand belonging to Yorkshire nursery Hippopotterings, where the feathery elegance of their Japanese maples is set off by a naturalistic sculpture of pheasants in flight by David Meredith.

Owner Pat Gibbons tells me that they've had a bit of frost damage, but still managed to find 100 perfect specimens for their display, which celebrates the 100th birthday of her grandmother next week. The worst problem they've had, though, says Pat, her face darkening, was being clamped that morning while they were grabbing a quick bacon roll. "£105 for breakfast – thank you very much," she says bitterly.

Months of frost and snow, lack of light, volcanic fall-out, riots – Chelsea's intrepid exhibitors can take these on the chin. But clampers, it seems, are right up there with snails, vine weevils, lily beetle and other lowest forms of gardening life.

The Chelsea Survivors' Guide

Garden designer Mark Gregory, above, has built nearly 50 gardens at Chelsea in 22 years and won gold medals for his designs last year and the year before. Here are his five tips for success.

It's all in the planning

Things always go wrong, so you have to have a "Get out of jail" card, or a Plan B. The art of writing a brief for a show garden is not to back yourself into a corner with something that isn't flexible.

Don't panic

If you hit a problem, sometimes it's better to walk away and come back fresh, rather than flounder about. Make sure you have lots of labour on standby, especially if bad weather kicks in. You can never have too much help but ...

You can have too much advice

Be very careful about listening to other people's opinions. Everyone will have one, but they won't necessarily tell you what they really think – they'll tell you what they think you want to hear. Stick to what you set out to do and don't deviate from the plan.

Don't be a fashion victim

It's very easy to be influenced by the design ideas going on around you, especially if you see all the other designers using a particular plant. But that final plant you feel you must get at the last minute is probably the one that will get you marked down by the judges.

Give yourself tweaking time

I like to allow time for the plants to settle in and relax. It also gives you time to look at the details. If you're building right up to the wire, there's no time to stand back and re-evaluate.