There are only 110 known kakabeak (Clianthus maximus), which Maori called ngutukaka, growing in the wild, mostly in central North Island. A tiny island in the Kaipara Harbour is the one site in Northland, with a single lonely surviving specimen of the once-plentiful northern variety.
The Roberton Island plants were propagated from a cluster of bushes found clinging to cliffs deep inside Te Urewera National Park, adjacent to Lifeforce Restoration Trust-owned land.
Those plants, which had survived because of their inaccessibility to predators such as snails, goats, deer and pigs, became the source of thousands of seedlings propagated by trust property manager, Pete Shaw.
A hybridised domestic variety bred from one original kakabeak has been available commercially for many years.
"That is a pretty inferior species with no genetic value whatsoever and doesn't bear a lot of resemblance to the native plant," Forest Lifeforce director and founder Simon Hall said.
Mr Hall is the executive chairman of Auckland food company Tasti Products, which provides a funding stream for the trust's activities.
He is also a friend of forestry-magnate Andrew Kelly, who offered his property on predator-free Roberton Island.
Mr Kelly said the kakabeak project was a continuum of work started by former owner Mike Alexander, whose extensive re-forestation programme on the once-farmed island saw him plant over 250,000 trees.
Mr Kelly has also planted hundreds of native plants over the past three years.
"I fell into the environment side of having this place," Mr Kelly said.
"I bought it because I wanted privacy and a view. I inherited by default something that was ecologically valuable."
There are five private properties on the western side of the island where Captain Cook landed in 1769, while the eastern side is DoC estate.
DoC Bay of Islands biodiversity manager Adrian Walker said the kakabeak project was an example of partnership that could help return other species, including birds, to the area.