Head Gardener Gary Long has said it is the best display of the estate's summer centre-piece since it was planted in 2008.
There are over 3,000 plants in the garden – ranging in size from miniature bushes to five-foot high standard roses and all sizes in between. There are also rambling and climbing varieties.
It was estate owner Michael Galsworthy's idea to introduce roses to Trewithen. He loves them and wanted to create a centre of excellence for roses in Cornwall – as well as a wow factor for visitors.
Gary said: "The whole effect is breathtaking. On a still warm morning the air is thick with the most amazing scent and the colours are so vibrant. It really is an outstanding display this year, probably helped by the cold winter which forced the plants to rest and gather strength to bud and bloom."
Gary explained that the heavy continual rain of last summer completely flattened the garden's roses but, so far, they have really enjoyed the weather this year.
The roses aren't the only summer flowers to benefit from the climate at Trewithen this year. The Chinese dogwood tree is looking particularly glorious with its stunning white bloom fading through to pink – although the colorful part is not a petal but a modified leaf, in the same way as a poinsettia.
Trewithen Garden is open to the public daily from 10am to 4.30pm until September 30th. Full details can be found on the website www.trewithengardens.co.uk.
Ends: 7 July 2011