The show stopping Cayman Islands underwater garden is in keeping with the amount of precipitation that the Chelsea Hospital shows have experienced in the past few days. Difference being that Chelsea’s first ever under sea garden conjures up the exotic warmth of that Caribbean idyll.

The exhibit is the result of a 4,500-mile collaboration between the Caribbean idyll and a Home Counties’ nursery and it recreates the jewel-like colours of the coral reefs surrounding the islands using drought tolerant plants available in the UK. The underwater effects are conjured up by cunning DVD and lighting effects.

This is the brainchild of Andrew Guthrie, manager of the Queen Elizabeth II Botanic Park on Grand Cayman and Steve Hendry, owner of Newington Nursery in Oxfordshire which specialises in hardy exotics.

A submariner garden might seem like one of Chelsea’s more far fetched aberrations until you hear land-based Caymaninans talking about the ocean floor as if it were their back garden and listen to dive masters like Nancy Easterbrook on Grand Cayman and Gladys Howard on Little Cayman telling visitors about ‘coral gardens’. The theme seemed obvious to Andrew who has been snorkelling around the Caribbean for 18 years.

"It is a new and exciting way of exhibiting plants," he says. "It highlights the fragility of the coral reefs, their importance to ecology and the ways in which they are being threatened. There’s no way we could tell this story using real coral and so we have found plants that mimic the underwater world in order to get our message across."

Anyone who has dived or snorkelled around Cayman will be familiar with the garden like qualities of the reefs: flowery anemones and richly coloured corals and seaweeds create underwater ‘borders’ on the seabed. Plunging down over a coral garden is like swimming into a kaleidoscope of red, yellow, green, blue and purple. The closer you look at a coral reef the more striking the similarities between the underwater world and the world above.

"Coral gardens demonstrate the delicate balance of life forms and their symbiotic relationships, much as you will find in your garden at home. Fish are to coral what bees are to plants," says Steve whose debut at Chelsea, back in 1999, featured the memorable theme of an aeroplane crash.

The challenge for Andrew and Steve was finding landlubber plants to conjure up a Caribbean underwater scene.

They discovered that deep red and orange cactus flowers, massed together to hide their stubby green bases, conjured up ruby and amber coloured coral. Graceful antlers of Staghorn ferns represent Staghorn coral; densely planted Euphorbias trace the tightly knitted ridges and runnels of brain corals and turtle grass, the brown/black seaweed that waves gently on the sea bed and shoreline, is mimicked by Black Mondo Grass - Ophiopogon planiscapus 'Nigrescens'. Plants like small Tillandsia, or airplants, and Cryptanthus bromeliads represent sea anemones.

The underwater atmosphere is heightened by projected images of stingrays and shoals of tropical fish gliding about over the ‘reef’. Those other rays, of sunshine, that beam through the underwater world are recreated using special lighting effects. The result is a display that gives visitors the closest thing to an underwater experience they are likely to have with their clothes on.

It is an evocative and brilliant exhibit but why should the Chelsea Flower Show, the world’s foremost garden catwalk, include a non-terrestrial theme?

"Without the protection of coral reefs the Cayman Islands would have a far poorer selection of plants and animals on land let alone underwater," says Andrew. "Coral reefs are an intrinsically important part of our natural environment. They contain a large percentage of our native animals and protect our marine environment and the islands themselves from storm surges during hurricanes."

This green theme is at the heart of the 21st century Chelsea Flower Show as well as this year’s Cayman Islands’ exhibit. It’s a far cry from last year when the Cayman Islands’ display could not claim many green credentials. Back then most of the plants were flown in from Cayman. Worse still, Andrew’s rare ghost orchids never arrived because they were confiscated by Dutch customs officials who, incidentally, have never returned the plants. This year there’s no chance of such an outrage - all the plants have been sourced in the UK.

"The ecological message is important to this garden. We want to make an exotic looking garden with minimum impact on the environment," says Steve.

Steve and Andrew’s joint entry last year marked the Cayman Islands’ first appearance at Chelsea. They were awarded a silver medal. This year they are hoping for gold.

"I felt that our exhibit should be completely different from last year’s," says Andrew. "I also wanted an exhibit that is very different from the other entries in the floral category. We will be competing against Jamaica, Grenada, Trinidad & Tobago, and Barbados – all of whom primarily use cut flowers such as Ginger, Heliconia, Bird-of-paradise and so on."

Either way the Caymanian exhibit, like the rest of the Caribbean displays, will add a splash of sunshine to Chelsea whatever the British weather decides to throw at this year’s show.

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