The RHS Chelsea Flower Show will be one of the most colourful for many years because of Britain's record heatwave, exhibitors and organisers predict.
But the hottest April since records began has also created chaos for top designers of the world-famous show gardens as plants bloom up to a month early.
They are rushing to redesign gardens costing up to £250,000 each that had been planned months ahead of the RHS showpiece. Many have swapped spring flowers for summer varieties rarely seen before at the show, which kicks off on 24 May.
Growers have had to swap greenhouses for fridges to try to stop popular flowers such as iris, lilacs, wisteria and lupins blooming too early for the show. Experts predict that tulips and peonies, normally Chelsea staples, will be exchanged for salvias and roses.
Bradstone Fusion garden mentor Chris Beardshaw said: "The weather is set to test everyone's understanding and tolerance. Normally, as soon as you see a bud on oriental poppies you know it is a month and a half before they will be fully in flower. That's all thrown out of the window this year.
"However, we will be able to bring in a range of summer plants that we were not considering for the show because it is too early in the year. For instance, strelitzia will be in flower. This year there will be a very different look to Chelsea because of the range of plants."
Skyshades designer Marney Hall said: "The season has been exceptionally difficult for growers. "It is a nightmare for many designers and I feel really sorry for them.
"Some designs are based around the colour of a particular iris and if you haven't got that you have to redesign and fly by the seat of your pants.
"There has been a lot of weeping and wailing and gnashing of teeth in various quarters this year. I found out my water irises and water primulas were over, which was not a high point for me. The flowers have just gone.
"But I will have plants such as spotted orchids, which I would never expect because they are usually in flower too late. They are ready nearly a month before you would expect them to be. We've had to find plants in nurseries further north in the country.
"I've had to force hawthorns into leaf in the past but this year they are nearly finished. All fruit trees have finished blossoming and I've had apple blossom at Chelsea in the past. I will have flowers on wild roses, which I've had to force before."
RHS shows director Stephen Bennett said: "The weather can change what a designer is planning to use in the way of plants. Last year, Chelsea displays looked very green after a cool spring. This year, the speed with which plants are coming into flower is staggering. We are going to see a much brighter, more colourful Chelsea."
David Domoney, designer
"The tricks of the trade at Chelsea are unbelievable, from using hairdriers to freezers to speed flowering up and to slow them down. Everyone has a fail-safe for a fail-safe for a fail-safe. You grow 10 times what you need and you heat some up and slow some down and hope to be able to use the middle ones. The weather has been unbelievable this year. The challenges beaten at the show are testament to the quality of the gardeners and the hard work that goes into the gardens."