The prolonged cold snap is producing some stunning frosty mornings – and leading the Eden Project’s gardening team to wrap delicate specimens with fleece for the first time.

To avoid plant casualties the team is using a variety of methods including fleece, straw and heavy mulch to keep plants warm in its outdoor gardens, which first opened to the public nearly ten years ago.

They are also replacing some exotic plants, such as Proteas, Acacias and Correas, with hardier selections.

Cornwall is renowned for its mild, temperate climate and relatively few frosts. Exotic plants from all over the world can be found in its parks and gardens. But the last few winters have been unusually harsh.

“Eden enjoyed exceptionally mild winters for the first seven years of its existence,” said horticulturist Darren Topps. “Borderline hardy plants like Pelargoniums, Gazanias and Dahlias all got through the winters no problem – and we were lulled into a false sense of security.

“This is the third year in a row that we have had a prolonged cold spell, with the ground frozen continuously throughout the day.” He said that temperatures plummet in Eden’s outdoor gardens in particular because they are planted in a 50-metre-deep former clay pit which acts as a ‘frost pocket’. Parts of the bowl which aren’t warmed by the low winter sun have reached as low as minus seven degrees this week.

Darren said: “We’re used to a mild climate down here in Cornwall – the county’s gardens are famed for unusual plants from warmer climes. More recently we’ve had a lack of summer sun and bitterly cold winters – not to mention the recent flooding. All we can say now is that the predictable has become very unpredictable.”

Yet there is a silver lining to the hoary frost: “The cold gives hardy and native plants a good rest, meaning they tend to flower their socks off the following spring or summer. The low temperatures also keep pests and disease in check. And of course the gardens look stunning in frost.”