Bodnant Garden staff have spent five years restoring Far End as part of the 80 acre (32 hectare) site, known for its botanical collections.
Laid out by creator Henry Pochin from 1874, Far End was designed as a wild garden.
The National Trust-run garden stretches over 10 acres (four hectares).
Far End includes a small lake, known as the skating pond, which has is its own island, as well as a boat house.
A section of a well known Conwy Valley garden has opened to the public for the first time since it was created 140 years ago.