The secret life of plants on Tiritiri Matangi – an island re-planted

Department of Conservation —  12/07/2021

Bringing the story of our native plants and trees to life takes special skill, especially when competing with our unusual and charismatic birds. But for readers of Dawn Chorus, Supporters of Tiritiri Matangi’s membership newsletter, 81-year old Warren Brewer weaves the worlds of linguistics, history, rongoā Māori and botany into a riveting read on flora found on Tiritiri Matangi Island.

Warren Brewer checking out karo flowers.
📷: Warren Brewer.

Lucky for us, Warren also takes guided tours of the island, unlocking the secrets of our native flora for anyone interested. The good news is that you don’t need to wait till spring to observe a flurry of floral activity. As winter approaches and the birds retreat into the bush, our plants and trees step up to the plate, showing anyone willing to slow down and look that they are just as astonishing as their feathered counterparts.

From bare beginnings to bursting with botanical wonders

Just forty years ago, Tiritiri Matangi, located near Auckland in the Hauraki Gulf Marine Park/Ko te Pātaka kai o Tīkapa, was almost completely bare of forest following 120 years of farming. Between 1984 and 1994, thousands of volunteers planted more than 250,000 trees and plants, ‘eco-sourced’ from seeds found on Tiritiri Matangi and nearby islands and raised in the island’s nursery. To boost plant biodiversity, a selection of species was introduced such as nectar-heavy kākā beak (Clianthus puniceus) and the rare tecomanthe vine (Tecomanthe speciosa).

Part of planning forest regeneration involves making sure you have enough nectar and fruit-producing plants and trees throughout the year for the native birds, lizards and invertebrates you are supporting. And boy, do winter-flowering plants and trees do it with style. You just need to know where to look, which is where Warren comes in.

Winter show-offs: Flower-sprouting tree trunks and gender reveals

Take for example the kohekohe tree, which behaves more like a tree from the tropics. This is because it is cauliflorous, producing its flowers and fruit directly from its trunk and main branches, rather than from new growth. Beautiful sprays of white orchid-like flowers bloom in early winter, providing nectar for tūī, korimako / bellbird and hihi / stitchbird. Stands of kohekohe like those found on Tiritiri Matangi are rare, and it’s been said* that standing amongst them is like ‘moshing’ with a crowd of Peter Garretts’ from Midnight Oil – think gangly limbs swaying akimbo!

Flowers of Kohekohe sprouting directly from the tree trunk.
📷: Warren Brewer.

Puahou / fivefinger (Pseudopanax arboreus) plants pick up the mantle in the middle of winter, flowering in June and July. What’s more, they let you know their gender as they are dioecious, meaning that each tree is either male or female. Male flowers have greenish-yellow petals and yellow-tipped stamens, the nectar of which is devoured by birds such as tūī, korimako, hihi and tauhou / silvereye. Female flowers on the other hand are smaller and drop their petals soon after opening, leaving just a large rose-red ovary with two styles on top. The flower oozes nectar from the style, looking a lot like a candy apple dripping with sugar syrup, which both birds and insects lick off.

The male flowers of puahou / fivefinger.
📷: Warren Brewer.

The small green ‘flowers’ of kawakawa round out winter flowering, although they more resemble spikes, lacking both petals and nectar. Like puahou, kawakawa are dioecious. Just before they are ready to disperse their pollen, the male flower spikes ripen to a dark grey and Warren likes to delight young visitors by gently flicking them, creating a smoky puff of pollen grains. Following pollination, the female spikes enlarge, growing tightly packed, orange-coloured fruits containing a peppery-tasting seed. The island’s Duvaucel geckos feast on them, as do tīeke, kōkako and kererū, aiding seed dispersal throughout the island.

Kererū days

At first glance, Warren’s life journey seemed unlikely to arrive at the vocation of botanical writer and island guide in retirement. Warren trained as a dentist, working successfully in his Manurewa clinic for many years. But scratch a bit deeper, and it’s clear that nature has been a comfortable companion since his youth, when he freely roamed the creeks and hills of his neighbourhood, Papatoetoe. Later, on his daily walk to work with a pre-schooler in tow, he would point out native trees and birds in bush remnants along the way. On one such walk, a kererū swooped by, coinciding with a cancellation of an appointment that day and therefore a reprieve. Forever on, good days were referred to as ‘kererū days’.

Once retired, Warren tagged along with his wife, Colleen, volunteering on Tiritiri Matangi Island with the Supporters of Tiritiri Matangi (SoTM). The reluctant speaker was cajoled into guiding and it was then that he realised how little he knew about the New Zealand bush and set about teaching himself.

Fifty-five issues, four drafts and one-fingered typing

Two hundred books and a handful of far-flung botany trips with the Auckland Botanical Society later, Warren now knows a thing or two. His interest was noted by the editor of Dawn Chorus, who asked him to write their regular feature ‘Flora Notes’, which he has penned for 55 editions and running. This is no easy feat as Warren is not what you’d call a ‘digital native’, writing out each article in longhand with up to 4 drafts, after which, in Warren’s words, “then begins the drama of typing with one finger.”

Warren’s wife Colleen in front of a giant mountain ash (Eucalyptus regnans) in Tasmania, March 2012, on an Auckland Botanical Society trip.
📷: Warren Brewer.

On reading Warren’s articles, it’s clear he has a curious mind. An article on edible seashore plants such as our rare native celery (Apium prostratum) touches on Captain James Cook’s quest to keep his sailors healthy on voyages. A ramble about pōwhiwhi (Ipomoea cairica), from the bindweed family Convovulaceae, leads into an explanation of how the name ‘potato’ was coined, via the dialect of a pre-Columbian people from Central America. And did you know the leaves from ngaio trees were used as an insect repellent by early Māori?

Native celery, Hobbs Beach, Tiritiri Matangi.
📷: Warren Brewer.

Warren’s dentistry background has also been an asset in his new vocation through his understanding of Latin – the technical language of botany. This insight provides clues to the plant’s features, as well as the humancentric way we make sense of the world. Take for example the shining spleenwort fern which has the Latin name Asplenium oblongifolium. ‘Oblongifolium’ refers to the oblong shape of the leaves, while ‘asplenium’ means ‘against the spleen’, referring to early European folklore that a fern-leaf infusion is effective against spleen or kidney disease. Importantly, the Māori names of plants are also explained, providing a distinctly local and often poetic layer of meaning. Shining speenwort is a case in point – ‘huruhuru whenua’ means ‘altogether glowing’, eloquently describing the fern’s tightly-packed, glossy, bright green fronds.

Shining spleenwort / huruhuru whenua
📷: Warren Brewer.

Recent editions of Dawn Chorus are only available to members, but you can read older articles of Flora Notes here. Better yet, you can arrange a tour with Warren by emailing During winter the ferry runs weekly on Thursday, Saturday and Sunday – check out the Fullers360 website for the timetable.

Love it, Restore it, Protect it

*Thanks to Kate Waterhouse from Great Barrier Island Environmental Trust for this excellent description of a kohekohe forest.

2 responses to The secret life of plants on Tiritiri Matangi – an island re-planted


    Beautiful and informative story… and a celebration of our environment – very inspiring, thank you.


    Nice work Warren and Colleen, volunteer s and writer of the story. I Enjoy others energy for the flora and fauna of NZ. So much to learn. 👍