 As secretary he bore the brunt of the administrative load of a body undergoing major change as it evolved from what had become largely a birdwatching club into a scientific conservation organisation undertaking ventures such as the Atlas of Australian Birds project.From 1980 Garnett devoted himself to developing the Garden of St Erth at Blackwood, Victoria, emphasising the use of Australian native plants in horticulture.The Garden was one of Australia's first private gardens opened to the public in the modern era.