Forget me not

Puha, sour thistle. Photo / Nick Reed

Auckland's rarest plants have epic survival stories, writes Kim Knight.

Think conservation, think kakapo and kiwi.

But birds aren't the only natives under threat. Since record-keeping began, New Zealand has completely lost six plant species. A further 8-10 per cent of the country's flora is under serious threat of extinction. The 2500 native plants on our mainland and offshore islands are massively outnumbered by 25,000 introduced exotics.

"Our plants are toughing it out," says Bec Stanley, curator at the Auckland Botanic Gardens. "Here in Auckland, we're got a high degree of urbanisation, and a really wonderful climate for weeds - it's really warm, things don't die in winter and we've got heaps of rain. We actually rival Honolulu as the weediest city in the world."

Weeds, animal pests and people have combined to push out plants. The Botanic Gardens' Threatened Native Plant Trail gives visitors a glimpse of some of the rarest locals left.

The 4000m-square garden is divided into habitats - from coastal rocky bluffs, to gumland and lava-fields. In its centre are two of the rarest plants in the world, after their populations were decimated by goats. Today, there are just one each of Pennantia baylisiana and Tecomanthe speciosa left growing in the wild (on Manawatawhi - part of the Three Kings Islands). They're the celebrities of this 10-year-old garden, says Stanley, but they're not the only stars.

Weekend took a tour of the trail where, as Stanley explains, every plant has an epic tale of survival.

PARAPARA
(Pisonia brunoniana): Used to grow on Auckland's waterfront, but no longer found on the mainland. Decline is attributed to predation by rats.

"It's a plant distributed by sea-birds. They don't land gracefully like an aeroplane, they crash into vegetation, and as they crash, these large sticky seeds get stuck to them. The plant wants to get to the next offshore island, and it sticks to a bird, it will get taken to a whole new place. The bird will preen the seed out, and it will grow.

"One of the problems with this in an urban environment is that the birds in your garden will get stuck - birds that are not endemic, like silvereyes, get caught. They shouldn't die, but then they get eaten by your cat... I like this plant - but it's very controversial. I say to people, "get rid of your cat, not your parapara"."

PUHA
(Sonchus kirkii): In decline across the country, mainly because of loss of its habitat to faster-growing introduced weeds.

"This is the native puha. When Maori came to New Zealand, they probably would have recognised this as an edible plant because of something they'd eaten in the Pacific. But after a while, European settlers came and they brought with them, probably via contaminated grass seed, S. oleraceus, its tiny cousin. After probably only 20 years it was more commonly encountered. Maori probably found the exotic one was tastier. They used the word 'puha' for it, which sort of gave it legitimacy. It made everyone think it was a native plant, and meanwhile the actual puha was starting to decline, to slip out the back door with nobody noticing. That's the insidious effect that weeds have."

VERONICA
(Hebe bishopiana): Only found in Auckland; grows on roadsides en route to Whatipu.

"This is really special, it's one of only three plants endemic to Auckland. It always looks like it's falling over, because that's what it has to do in nature - it tumbles over rocks and waterfalls. We're not in the glamour part of the Botanic Gardens, but this is a pretty garden plant, because it does flower heaps. It's about training your eye into thinking that not everything precious is beautiful, and not everything valuable is beautiful. When you're looking at conservation, it's not all about the kakapo.

"Waitakere is the only place in the world this grows. If there was a volcanic eruption in Auckland, it would be lost forever, but that's probably unlikely. We're not working on that catastrophic level. What threatens this is weeds... One of the main threats was an exotic plant called mistflower, and that's pretty much not a weed anymore, because of a biocontrol fungi that was brought in. I hope this means the hebe will recover."

FORGET-ME-NOT
(Myosotis pansa): There are about 100 forget-me-nots in New Zealand. Thirteen are threatened with extinction, including this one, endemic to Waitakere.

"It likes gaps and edges, and it would have danced around the landscape finding open sites, but as we started building those out and encasing them in concrete and changing the environment around, it lost all those open sites.

"In 2000, I decided to GPS map it. I walked from Whatipu to Te Henga, its full range. And then I re-did that in 2009 and found it had actually increased in population - there were 700 left in the wild, compared to 550 in 2000. Why would I spend so much time on one plant? I felt like it was a good emblem. Whatever is happening to this plant, is probably happening to 20 or 50 others."

Need to know

Botanic Gardens, 102 Hill Rd, Manurewa

Winter hours (April to September)

• The Gardens are open daily from 8am to 6pm.
• Visitor Centre Huakaiwaka open from 8am to 4pm.
• Cafe Miko is open daily from 8am to 4pm.