Cordyline australis

A New Zealand tree shaped by open, moist landscapes

Cordyline australis is a woody monocot native throughout New Zealand, where it is known as tī kōuka or the cabbage tree. Young plants begin as fountains of narrow leaves; older specimens raise those crowns on branching trunks.

In nature it occupies forest edges, river terraces, wetland margins and other open ground from the far north into the cooler South Island. These places experience regular rain, wind and changing maritime temperatures. Tough leaves and substantial underground stems support new crowns in both exposed gaps and sheltered, moisture-rich sites.

Light, moisture and root care

Managing height, branches and old leaves

The plant develops a trunk and needs no stake if the pot is stable and light reaches the crown evenly. Rotate Cordyline australis before a pronounced lean develops, using small staged turns.

Strong light for dense green leaves

Place it directly at a bright south-, west- or east-facing window where the whole crown receives strong daylight. A sudden move into intense summer sun can leave papery patches, while too little light produces softer, more widely separated leaves and a stem that reaches towards the window.

Deep watering beneath the green crown

Wait until the upper layer of the substrate around Cordyline australis is dry and the pot is distinctly lighter, then soak the root ball and drain it fully. Confirm moisture within the root zone before repeating the soak.

A cooler winter for Cordyline australis

Mild indoor conditions suit active growth; in winter, a brighter, cooler, frost-free position is acceptable when watering is reduced. Keep a potted Cordyline australis frost-free and do not leave wet roots against freezing glass.

Air around long, tough leaves

Normal household humidity is sufficient for Cordyline australis. Its firm narrow leaves gain little from artificially high humidity; open space and moving room air around the trunk are more useful.

Nutrition for trunk and root growth

Apply a balanced complete fertiliser at a low dose sparingly while Cordyline australis is producing roots, leaves or trunk growth. Reduce the dose after repotting and whenever cool or dim conditions slow growth.

Problems to check on Cordyline australis

The lowest sword leaves yellow and hang down

A few of the oldest leaves naturally die as the cabbage tree exposes its trunk. This is normal when the stem is hard and the central spear is extending. Remove only fully brown leaves. Rapid yellowing through the whole rosette, especially in wet compost, points to stressed roots.

Leaf tips turn brown while the rest stays green

Irregular tip burn usually follows uneven drying, accumulated fertiliser salts, very hard water or a cold draught. Check moisture below the surface and flush excess salts from a freely draining pot. Trim only the dead tip. Brown bands appearing after a cold night are cold injury, not a request for more water.

The crown becomes pale, loose or strongly one-sided

New leaves produced in weak light can be longer, softer and more widely spaced; a tall, top-heavy plant may then lean towards the window. Increase light gradually, turn the pot periodically and stabilise the root ball. A firm leaning trunk can be supported; a soft or cracking base needs an immediate root and stem check.

The centre leaves flop after frost or cold rain

The growing point may have been cold-damaged. Leave firm tissue in place until the extent is clear, then remove dead material with clean tools; a sound trunk can reshoot below the injury. Act faster if the centre is brown and soft or the stem releases foul-smelling ooze, as secondary crown or stem decay may be developing.

Cordyline australis is toxic to people and pets

• Keep this plant away from children, cats and dogs.
• It contains saponins that can irritate the mouth and digestive tract.
• Chewing may cause drooling, vomiting, stomach pain, reduced appetite or weakness. Contact a veterinarian or medical professional if symptoms develop.

What does Cordyline australis mean, and who first published it?

Cordyline comes from Greek kordyle, meaning club, referring to its thickened underground stems. The epithet australis means southern.

Robert Brown established the genus Cordyline in 1810 in Prodromus Florae Novae Hollandiae, page 280; Philibert Commerson had proposed the name.

Johann Georg Adam Forster first described it as Dracaena australis in 1786 in Flora Insularum Australium, page 24. Stephan Friedrich Ladislaus Endlicher later placed it in Cordyline as Cordyline australis in 1833 in Prodromus Florae Norfolkicae, page 29.