Tī Kōuka: The Cabbage Tree (4 minute read)

Possibly Aotearoa's least loved native tree, but a year-round provider for wildlife

Apr 06, 2024

Good morning☀

After a brief (and unplanned) hiatus last month I am taking a few days out to focus on writing. I have a couple of subjects for the Dwindle River Garden in mind, but as I sit here typing I can see three rather magnificent trees outside my window: a cabbage tree, a pōhutukawa, and a eucalyptus.

My view from the window at Federation House, Ōamaru.

We don’t see many pōhutukawa here in Te Wai Pounamu (the South Island) - which is a bit of a cultural shock after the red-carpeted streets of Auckland at Christmas time! We have plenty of cabbage trees, though.

I have several favourite trees in my garden, and among them is one particular cabbage tree (Cordyline australis). It provides a basking spot for insects who need to warm up, a foraging area for birds, and kai (food) for all when it is flowering. I love its chunky patterned bark, and the artfully twisted silhouette it creates against the sky.

A magnificent cabbage tree (Cordyline australis, endemic) at sunset in Waikouaiti.

There are uses for humans, too. Māori used cabbage trees as a food, fibre and medicine1, and at home we sometimes use the dried leaves as kindling. Famously, its leaves were boiled and eaten like cabbage by Captain Cook and his crew which gives this tree its common English name. Today we’ll look at some of its uses for wildlife.

Food

When the flowers bloom in early summer there is a buzz of activity around our cabbage trees. Everything from birds, to bees, to butterflies and moths, and millions of tiny nameless insects feast on the flowers. I’ve yet to see any lizards in our backyard, but the flowers are also a food source for geckos2.

The flowers are arranged along stems, called an inflorescence,3 with five to ten thousand flowers on each inflorescence. So, there is plenty for everyone!

New Zealand red admiral (Vanessa gonerilla, endemic) feeding on cabbage tree nectar (Cordyline australis, endemic).

After the flowers come the berries, which keep the food going for the birds, and of course this also means seed dispersal for the trees. Birds can hunt the insects and spiders sheltering in the foliage.

Sunbathing

When the gnarly bark of the cabbage tree soaks up the sun, it becomes a perfect ‘sunning’ or ‘basking’ spot for insects like butterflies, who are cold-blooded and need to warm up in order to fly.4 It’s become a favourite spot for the butterflies in our garden, and I’ve also seen flies and bumblebees using it to thermoregulate.

A close up in my garden at home with a yellow admiral butterfly basking (Vanessa itea, native).

Shelter

The dense growth of foliage, combined with its branching habit, makes little nooks and crannnies that are perfect for insects and spiders to shelter in. Below you can see some magpie moths sheltering amongst the dry leaves at the wetland walk in Macraes. There were several more resting on the trunk of this tree - they seemed to really love it.

Nesting

Kāhu (swamp harriers, native to New Zealand, Australia, and several Pacific Islands) will use cabbage tree leaves to build their nests.5

According to DoC, hollows in cabbage trees provide important roost sites for our native long-tailed bats, so if you are lucky enough to have bats around your area then hopefully you have some cabbage trees, too!

Image from the Proceedings of the Zoological Society of London 1857 (Public Domain)

Tī kōuka have become so ubiquitous that it is easy to take them for granted. Could you take some time this week to stop and appreciate one in your neighbourhood? Can you see its white berries, or maybe the last of its flowers? What birds, insects, spiders, or lizards are using it?

Happy autumn,

Zenobia🍂

Dwindle River Garden