Tī kōuka
Cordyline australis
Tī kōuka, also known as the cabbage tree, is a distinctive and iconic New Zealand plant with long, sword-shaped leaves and tall flowering spikes. It is valued for its resilience and cultural significance. native trees
Image credit: Cabbage Tree (Cordyline australis) showing its distinctive crown of leaves. Image by Phil Bendle [CC BY-NC-ND 3.0], via Wikipedia
Quick Facts
| Height | 5-10 meters |
|---|---|
| Water Needs | Moderate |
| Light | Full sun to part shade |
| Frost Tolerance | High |
| Growth Rate | Moderate to fast |
| Lifespan | Several hundred years |
Climate Best Suited To
The Cabbage Tree is incredibly adaptable and grows throughout New Zealand from coastal areas to lower mountain areas up to about 1000m. It is tolerant of a wide range of conditions, from hot and dry to cold and wet.
Regional Suitability
| City | Climate Suitability |
|---|---|
| Whangārei | Ideal |
| Auckland | Ideal |
| Hamilton | Ideal |
| Tauranga | Ideal |
| Rotorua | Ideal |
| Gisborne | Ideal |
| New Plymouth | Ideal |
| Napier | Ideal |
| Whanganui | Ideal |
| Palmerston North | Ideal |
| Wellington | Ideal |
| Nelson | Ideal |
| Christchurch | Ideal |
| Dunedin | Moderate |
| Invercargill | Moderate |
Growing Requirements
Soil Requirements
Cabbage Tree is remarkably adaptable to different soil conditions:
- Tolerates a wide range of soil types from clay to sandy
- Prefers well-draining soils but can handle occasional waterlogging
- Thrives in moderately fertile soils but will grow in poor soils too
- Can tolerate slightly acidic to slightly alkaline pH
- Handles coastal conditions including salt spray
Light Requirements
Cabbage Trees are sun-lovers that perform best with:
- Full sun for optimal growth and form
- Can tolerate partial shade but may develop a leggier form
- At least 6 hours of direct sunlight daily is ideal
- Northern or eastern exposures work well in garden settings
Water Requirements
Once established, Cabbage Trees are drought-tolerant:
- Moderate watering during establishment (first 1-2 years)
- Drought-tolerant once established
- Can handle periods of soil saturation
- Reduce watering in winter when growth slows
- Signs of overwatering include yellowing leaves and crown rot
Uses & Significance
Garden Uses
- Specimen tree
- Coastal gardens
- Native gardens
- Architectural accent
- Erosion control on slopes
Cultural Significance
- Important food source in traditional Māori culture
- Young leaves used for weaving
- Medicinal uses in rongoā Māori
- Marker tree for trails and boundaries
Ecological Value
- Food source for native birds
- Habitat for insects and small animals
- Soil stabilization
- Natural shelter belt
Seasonal Care Calendar
Spring
- New growth begins
- Apply a balanced fertilizer if desired (though not usually necessary)
- A good time to plant new specimens or divide offsets
- Monitor for new pest activity
Summer
- Flowering typically occurs in early summer
- Water young trees during extended dry periods
- Look out for infestations of cabbage tree moth caterpillars
- No pruning needed during the growing season
Autumn
- White or cream berries develop and ripen
- Natural leaf shedding occurs (normal part of growth cycle)
- Good time for planting new specimens
- Clean up fallen leaves if desired
Winter
- Generally dormant with minimal growth
- No special winter protection needed in most of New Zealand
- Suitable time for pruning if needed
- Fallen leaves can be left as mulch or removed for tidiness
When to Prune and How Much
Cabbage Trees generally need minimal pruning:
- Remove dead, damaged or diseased branches at any time
- To create a multi-trunked specimen, cut the main stem to encourage branching
- Fallen leaves can be removed for a tidier appearance, or left for a more natural look
- If necessary, lower branches can be removed to create clearance underneath
- Major pruning is best done in late winter to early spring
Always use clean, sharp tools for pruning to minimize the risk of disease. The cut stem often branches, creating a more bushy appearance.
Planting Guide
When to Plant
The best time to plant Cabbage Trees is during autumn or spring when soil temperatures are mild and rainfall is typically more reliable. This gives the roots time to establish before extreme heat or cold.
Site Selection
Choose a site with:
- Full sun to partial shade
- Well-draining soil (though adaptable to most soil types)
- Protection from strong winds for young plants
- Adequate space for mature growth (5-10m tall and 2-3m spread)
Planting Procedure
- Dig a hole twice as wide and the same depth as the root ball
- Add compost or well-rotted manure to heavy clay soils to improve drainage
- Position the plant so the crown sits at soil level
- Backfill with soil, gently firming down to remove air pockets
- Create a watering basin around the plant
- Water thoroughly after planting
- Apply a 5-10cm layer of mulch, keeping it away from the trunk
Initial Care
Water regularly during the first growing season, especially during dry periods. After establishment, cabbage trees are quite drought-tolerant but will grow more lushly with regular watering.
Propagation Methods
From Seed
Growing cabbage trees from seed is relatively straightforward:
- Collect ripe white berries in late summer to autumn
- Remove pulp and clean seeds
- Sow immediately in seed-raising mix at a depth of 5mm
- Keep moist but not waterlogged
- Germination usually occurs within 3-6 weeks at 20-25°C
- Transplant seedlings when they reach 10cm tall
Seedlings typically flower after 6-10 years.
From Offsets
Mature cabbage trees often produce offsets or "pups" at the base:
- Carefully dig around the offset to expose the connection to the parent plant
- Cut the offset cleanly from the parent with a sharp, sterilized knife
- Allow the cut surface to callus for 24 hours
- Plant in a container with free-draining potting mix
- Keep moist until established, then plant out
From Stem Cuttings
Trunk sections can be used to propagate new plants:
- Cut a section of trunk about 30-50cm long
- Allow cut ends to callus for several days
- Plant horizontally with half the cutting above soil level
- Water sparingly until new growth appears
Cultural History
The Cabbage Tree (Tī kōuka) holds profound significance in Māori culture and history, serving as both a practical resource and a cultural symbol for generations:
Traditional Uses
- Food Source: The roots and young shoots were cooked in earth ovens (hāngī) to produce a sweet food called kāuru, rich in carbohydrates
- Medicine: Various parts were used to treat wounds, diarrhea, and other ailments
- Fiber: The leaves provided durable fiber (muka) for making sandals (pāraerae), waterproof rain capes, and baskets
- Shelter: The leaves were used for thatching temporary shelters
Cultural Significance
- The trees were often planted to mark trails, boundaries, and urupā (burial grounds)
- They served as markers for good fishing and eeling spots
- Their distinctive form made them important landmarks for navigation
- Plantings often indicated the location of marae (meeting grounds) or settlements
- Certain trees were considered tapu (sacred) and associated with tribal histories
Early European History
- Early settlers used the leaves as emergency food for cattle during droughts
- The young inner shoots were sometimes eaten as a substitute for cabbage (hence the common name)
- The trees became iconic features of the developing pastoral landscape
- They were commonly planted as specimen trees around homesteads
Contemporary Cultural Role
Today, the cabbage tree continues to be an iconic symbol of New Zealand identity, featuring in art, literature, and landscape design. The species has come to represent resilience and adaptation – qualities shared by both the plant and the peoples of Aotearoa New Zealand.
Pests & Diseases
Sudden Decline Syndrome
- Cause: A phytoplasma (bacterial pathogen) spread by introduced passion vine hoppers
- Symptoms: Leaves yellow and die from the crown down; leaf bases often rot inside the crown; leaves fall but remain hanging down the trunk
- Management: No cure is available. Remove and destroy affected trees to prevent spread. Plant resistant selections where possible
Cabbage Tree Moth (Epiphryne verriculata)
- Damage: Caterpillars feed on leaves, creating distinctive notched patterns and sometimes completely defoliating young plants
- Symptoms: Semicircular notches around leaf edges; webbing between leaves; caterpillar frass (droppings)
- Management: Natural infestation is rarely serious enough to warrant control. For severe cases on small plants, remove caterpillars manually or apply Bacillus thuringiensis spray
Leaf Spot Diseases
- Cause: Various fungal pathogens including Septoria species
- Symptoms: Small brown or black spots on leaves, sometimes with yellow halos; spots may enlarge and merge in severe infections
- Management: Improve air circulation; avoid overhead watering; remove severely affected leaves; apply copper-based fungicide for valuable specimens if necessary
Root and Crown Rot
- Cause: Phytophthora and other soil-borne pathogens, usually associated with poor drainage
- Symptoms: Wilting despite adequate soil moisture; yellowing leaves; slow growth; soft, discolored tissue at the crown
- Management: Improve drainage; avoid overwatering; ensure crown is not buried too deeply; avoid soil compaction around the base
Other Pests
- Scale insects: Can colonize leaves and stems, causing yellowing and reduced vigor
- Mealybugs: Sometimes infest the crown and leaf bases
- Rabbits and hares: May damage young plants by chewing bark and shoots
Most established cabbage trees are resilient enough to recover from pest and disease issues without intervention. For valuable specimen trees, consult with a professional arborist or horticulturist for specific treatment recommendations.
Bonus Tip
To create a dramatic nighttime feature, position outdoor lighting to shine upward through the crown of your Cabbage Tree. The architectural form creates stunning shadows and silhouettes, especially effective against a wall or fence. This works particularly well with multi-trunked specimens that create complex patterns of light and shadow.
Cultural Significance
Learn more about the cultural significance of native trees in Cultural Plants.