The Clan McNeill became the undisputed Lairds in 1590 after a fierce power struggle between the MacDonalds and the McNeills. At the end of the 19th century Captain William Scarlett, the 3rd Lord Abinger purchased the estate and built the listed B Achamore House in 1884 to the design of John Honeyman.
The main areas of woodland to the north and south of the house were planted by William Scarlett to provide shelter from the strong winds and salt spray and game cover. When Col. Sir James Horlick acquired the estate in 1944 he wished to establish a garden to grow his more tender Rhododendrons. He managed this by cutting small clearings in the Ponticum and trees and by 1970 the garden was full and looked magnificent.
On his death he left some of his collection to the National Trust for Scotland so that rare species could be propagated and shared with other great gardens.
The 50 acre gardens offer a truly dazzling variation in settings, being sub-divided into over 15 differing areas. Gigha lies at the extremity of the Gulf Stream and as such has a climate of a very temperate nature. This allows species of plants and shrubs to prosper here which are very rare on the West Coast of Scotland, especially rhododendrons.
The walled gardens provide a sheltered habitat for not only rare and unusual plants and trees, but also peacocks! Greenhouses provide an ideal environment for propagating new plants and unusual species.
On the 15th March 2002 the Island was purchased in an historic buy-out by the inhabitants of Gigha. The gardens are now entrusted to the people of Gigha and they provide a wonderful backdrop to Achamore House.