IT is the Oscars of the horticultural world.

Hundreds of professionals and enthusiasts spend months meticulously preparing for the gardening showpiece billed as the greatest plant show on earth.

But a Hampshire nursery’s £10,000 entry for the Chelsea Flower Show faces possible disaster – because of plummeting temperatures.

Hillier Nurseries and Garden Centres near Romsey fears its chances of winning a coveted 65th consecutive gold medal are in peril because of the continuing cold weather.

A team of around 30 gardeners have been growing the 200 roses, 100 foxgloves and 200 rhododendrons and azaleas for a 3,500-plant display centrepiece since January.

In a desperate bid to hurry the growth of the plants along, staff have erected polytunnels to concentrate the warmth in the run up to the competition.

Hillier’s Ricky Dorlay said: “I have been preparing plants for the show for over 40 years, and I can never remember such a miserable spring.

“It could be a very green Chelsea, maybe more green than gold.”

A spokeswoman for the Met Office said plants could have been affected by the unusually cold winter or the lack of rainfall in April.

She said on average temperatures were 3C (37F) in December to February, well below the 30-year winter average of 4.8C (41F). During January much of Hampshire was covered by snow which brought parts of the county to a standstill.

To make matters worse April rainfall was half of what would normally be expected and forecasters are not predicting a great deal of rain leading up to the show from May 25-29.

Managing director Andrew McIndoe, who leads Hillier’s Chelsea team, said: “These low temperatures are not a problem to work in, but I am afraid many of the plants we are depending on will not make it to the show.

“The trees are my first concern, these have to remain outdoors and many are still not in full leaf.”

It is not the first time in recent years that mixed up weather has hampered Chelsea plans.

In 2007 gardeners complained their preparations for the event, which attracts more than 150,000 people, were being held back by unseasonably warm weather, meaning plants were flowering too early.