Gary Long has wrapped the garden's most delicate exhibits in fleeces to protect them from any frosts and biting icy winds.

Although many other gardeners use this technique it's the first time Gary has felt any need to use it at Trewithen. Predictions of frost usually come to nothing in Cornwall but after the prolonged freezing temperatures of earlier this month he would rather be safe than sorry.

First to be covered were the two species of banana grown on the estate, which lies between Truro and St Austell. The Japanese Musa basjoo and Chinese Musa lasiocarpa grow in Trewithen's water garden, which is extremely sheltered but surrounded by trees that block any ice-melting direct sunlight for most of the day.

The garden's New Zealand Christmas Tree – Metrosideros excelsior – has also been wrapped up. Originating in the southern hemisphere it is covered with red bottlebrush-like flowers for Christmas in New Zealand. Gary is trying to acclimatise it to British weather and encourage it to flower during our summer.

Trewithen's Schefflera macrophylla, which originally came from Fan Xi pan in North Vietnam, is another Trewithen tree wearing a fleece. It is the only one of its kind in England and its architectural foliage has flourished in the estate's mild, sheltered climate. Staff are determined not to lose it to the weather.

Gary said: "The threatened frosts may never materialise but I'm not prepared to risk it. We've worked hard nurturing these plants and they're very expensive. I'm going to do everything I can to protect them."