For the last few years the estate's famous Camellia and Magnolia trees have been flowering progressively earlier, but this year the cold has slowed their growth by more than a month which means they will be in full bloom when the garden re-opens to the public on Sunday, March 1st.
Many other local gardens are reporting substantial losses amongst their tender plant species, thankfully there have been no major casualties at Trewithen.
The National Trust has said that the severe weather has damaged more than half the plants in some of its gardens and although the damage can be repaired it will take time.
"We've been extremely lucky," said owner of Trewithen, Michael Galsworthy. "So many of Cornwall's gardens have suffered during the frost, snow and high winds we feel very fortunate. If anything the weather has been beneficial to the species we grow.
"The spring-flowering trees and bushes have slowed meaning they will be at their absolute best when we open to the public. Even the daffodils are maturing much later this year and, for our newly established rose garden, it has been the best possible conditions for an excellent display in the early summer."
Mr Galsworthy explained that lack of frost during the winter is often the reason roses do not flourish in Cornwall. The plants are famous for not resting unless temperatures drop which can make them look tired during the peak flowering months.
The Trewithen rose garden – the only public rose garden in Cornwall – was planted early in 2008. It has grown and developed since then and after the benefit of the severe winter frosts its future looks particularly bright.