Some native species could disappear forever as Auckland's urban sprawl forces plant nurseries to close.
Botanists and garden gurus also warn of a dumbing down of plants and the favouring of commercial varieties over natives as more and more nurseries close down.
Plant nurseries close to cities, such as Auckland, are shutting down in part due to an aging workforce, but also because land for subdivisions is so highly sought after.
In West Auckland alone two nurseries with decades' worth of experience have closed and another, Oratia Native Plants, is on the market.
Geoff Davidson started Oratia Native Plants in the 1970s.
He spent the four decades since growing, nurturing and in many cases helping bring back from the brink of extinction numerous native species - including the Pennantia baylisiana - which was at one point the world's rarest plant.
About 10 years ago, he came across a "creeping hairy herb" in a property in North West Auckland, which he helped to grow and got DNA tested.
"It turned out to be a brand new species, new to science, never seen before, never described ... and it's Auckland's only true endemic plant."
It's since been given the name Parahebe jovellanoides.
That plant and thousands more native to New Zealand are grown and sold on the 6 hectare site in Oratia.
But the place is up for sale - Mr Davidson has recently turned 70, and is keen to retire.
There is a developer interested in the place, who "will probably hang on to it for ten years ... change the zoning ... and then there will probably be highrises here."
His nursery is one of many that have shut up shop.
Botanist Peter de Lange said there was a real risk that some native plant species would disappear as the expertise and land was lost.
He said New Zealand used to celebrate diversity in its plants.
"Now what we have is a series of commercial lines that are producing the same thing over and over again, usually hybrids, often things that actually aren't correctly identified. And they've squeezed out or undercut the specialist nurseries," he said.
Mr de Lange is at Unitec now, but previously spent almost three decades at the Department of Conservation as a principal science advisor - and "threatened species expert."
"Plant conservation needs nurseries ... and the New Zealand people need specialist native plant nurseries. We don't need all these horrible hebe hybrid, you're not really growing a native plant, you're growing a mutated freak that somebody produced for fun."
It was not just the plants at risk, but also the loss of a wealth of knowledge.
Philip Smith is a landscape gardener who specialises in using native and rare species in his clients' gardens.
"You go into one of these nurseries for one plant, and you come away learning about six others and suddenly you're a genius, because they made you a genius ... you just come away a lot more intelligent than when you went in the gate"
Mr Smith said it was important people embraced what was native and special to New Zealand.
"They're just an abstract concept when they're out in the wild ... horticulture and landscape design is a lens through which people can learn more about them."
