A garden was first made on this site in 1865 by T.H. Potts, New Zealand's first botanist and conservationist. Potts planted a great variety of exotic trees and shrubs, many of which still stand on the perimeter of the garden and on adjacent properties. When he died in 1888 the garden fell into dis-repair until it consisted of little more than a lawn around the house. Sir Miles Warren and Mr and Mrs Trengrove restored the house and began the present garden in 1977. Sir Miles along with a team of great people, now run the garden.
In 2012 Sir Miles gifted the homestead and gardens to New Zealand including a fund administered by the Ohinetahi Charitable Trust to cover upkeep. Ohinetahi has received the Garden of Distinction and Garden of Excellence Award and the homestead is registered as a Category I heritage building with the New Zealand Historic Places Trust ^[1].
This is the locality where Potts planted 117 specimens of 77 different conifers in 1866 and where the recording and measurement of the growth of trees is considered to have begun in New Zealand. The subsequent results were published the Country Journal ^{[2 & 3]} (Cadwallader, B. 2015)

References:
1) Ohinetahi In Wikipedia, Retrieved February 20, 2015.
2) New Zealand Country Journal (1878, 1 November). Through a young plantation [Part 1], 11 (6): pp. 390-397.
3) New Zealand Country Journal (1879, 1 January). Through a young plantation [Part 2], 111 (1): pp. 34-38.