Great Gardens of Cornwall
This is a useful website giving you a good impression of various gardens worth visiting in Cornwall. We would recommend the Eden Project, the Lost Gardens of Heligan, as listed below, and Caerhays to name a few. However the website gives a good description of all the gardens in the area, provides links to their individual websites and has any contact information you would require.
URL – www.greatgardensofcornwall.co.uk