Trebah Garden is a superb old Cornish garden, started in the 1840's.  25 acres of sub tropical ravine running from the 18th century house through cascading water gardens with Koi Carp, glades of tree ferns, hydrangeas and rare species, down to a private beach on the Helford River. This is ideal for picnics and has superb views over the river mouth.
Extensive plantings of sub-tropical plants at the top of the Trebah Garden blend into rainforest of the lower reaches.
3 acres of hydrangeas give superb autumn interest.
Children's trail all the year round.
The Trebah Garden Web Site is excellent.

Trebah Garden - Open all year,  
10 30 am to 5 pm. Dogs on lead, refreshments, OK  for wheelchairs but some paths steep , plant sales. 

Gardens in Cornwall map