How to grow new zealand cabbage tree
Overview
Cordyline australis, commonly known as New Zealand cabbage tree, is a striking, palm-like tree native to New Zealand. It is grown for its architectural form, long sword-shaped leaves, and panicles of creamy-white flowers in summer. This tree is exceptionally tough, tolerating coastal winds, drought, and poor soils once established.
Varieties
- Cordyline australis 'Red Star' — Compact cultivar with deep burgundy-red leaves, ideal for smaller gardens and containers.
- Cordyline australis 'Purple Tower' — Upright form with purple-bronze foliage, reaching 3–4 metres tall.
- Cordyline australis 'Torbay Dazzler' — Variegated leaves with cream and green stripes, adding bright contrast to the garden.
Soil Preparation
Prefers well-drained soil with a pH between 6.0 and 7.5. Tolerates sandy, loamy, and even clay soils provided drainage is adequate. Improve heavy clay with gypsum and organic matter before planting.
Growing Guide
Plant in a position with full sun to part shade, ideally with protection from harsh afternoon sun in hotter climates. Space trees at least 2–3 metres apart to allow for their mature spread. Dig a hole twice the width of the root ball and plant at the same depth as in the container. Water in well and apply a layer of organic mulch around the base, keeping it clear of the trunk. For best results, plant in spring or early autumn to allow roots to establish before temperature extremes.
Sowing
Sow seeds in spring in a seed-raising mix, covering lightly with soil. Keep moist and warm (18–24°C); germination takes 4–8 weeks. Seedlings can be transplanted when they reach 10–15 cm tall. Direct sowing is not recommended; start in pots for best results.
Care
Feed with a balanced slow-release fertiliser in early spring. Remove dead or damaged leaves as needed to maintain a tidy appearance; the plant naturally sheds lower leaves. No regular pruning is required, but you can cut back the central leader to encourage branching if desired.
Companion Planting
Pair with other structural plants like Phormium tenax (New Zealand flax) and Astelia chathamica (silver spear) for a cohesive native look. Underplant with low-growing groundcovers such as Coprosma 'Hawera' or Libertia peregrinans to create contrast. Avoid planting directly beneath dense canopies that will compete for light and moisture.
Common Pests & Risks
Scale insects can appear on leaves and stems; treat with horticultural oil or insecticidal soap. Leaf spot (fungal) may occur in humid conditions; improve air circulation and avoid overhead watering. Mealybugs occasionally infest leaf axils; remove by hand or use a systemic insecticide if severe.
Troubleshooting
Yellowing lower leaves: natural ageing; remove as they die. Brown leaf tips: often due to dry air or salt buildup; flush soil with fresh water. Leaf spots: fungal infection; improve air circulation and avoid wetting foliage. Stunted growth: may indicate poor drainage or root rot; check soil moisture and amend if needed. Scale insects: small brown bumps on stems; treat with horticultural oil.