Whekī
Dicksonia squarrosa
The whekī ponga (Dicksonia squarrosa) is a common tree fern in New Zealand forests. Learn more about New Zealand ferns and their habitats.
Image credit: Whekī (Dicksonia squarrosa). Wikipedia
Quick Facts
| Scientific Name | Dicksonia squarrosa |
|---|---|
| Height | 4–6 m (occasionally up to 10 m) |
| Spread | 2–3 m |
| Water Needs | Moderate to high; keep soil consistently moist |
| Light | Dappled to deep shade |
| Frost Tolerance | Moderate; tolerates light frosts when established |
| Salt Tolerance | Low; does not tolerate salt spray |
| Growth Rate | Moderate to fast |
| Lifespan | Long-lived (decades) |
Whekī is native to the forests of New Zealand, where it thrives in cool, moist, sheltered environments. It is found throughout the North Island and in the northern and western parts of the South Island. It prefers areas with consistent moisture, protection from strong winds, and moderate temperatures.
Regional Suitability
| City | Suitability |
|---|---|
| Whangārei | Ideal |
| Auckland | Ideal |
| Hamilton | Ideal |
| Tauranga | Ideal |
| Rotorua | Ideal |
| Gisborne | Moderate |
| New Plymouth | Ideal |
| Napier | Moderate |
| Whanganui | Ideal |
| Palmerston North | Ideal |
| Wellington | Ideal |
| Nelson | Ideal |
| Christchurch | Moderate |
| Dunedin | Moderate |
| Invercargill | Challenging |
Soil Requirements
Whekī performs best in the following soil conditions:
- Rich, humus-filled soil
- Good moisture retention
- Well-draining but consistently damp
- Slightly acidic to neutral pH (5.5-7.0)
- Benefits from added leaf mold or composted pine needles
- Tolerates poor soils if moisture is adequate
Light Requirements
This tree fern prefers shaded conditions:
- Dappled to deep shade
- Protection from direct sunlight, especially midday sun
- Morning sun tolerated in cooler regions
- Ideal under canopy of taller trees
- Can tolerate more light if soil remains consistently moist
- Young plants need more shade than established specimens
Water Requirements
Whekī has moderate to high water needs:
- Regular watering, especially during establishment
- Keep soil consistently moist but not waterlogged
- Water both the crown and soil during dry periods
- Mulch to retain soil moisture
- Reduce watering slightly in winter
- Increased watering needed during hot, dry periods
Temperature Tolerance
Whekī has the following temperature preferences:
- Prefers moderate temperatures
- Ideal growing range: 10-25°C (50-77°F)
- Can tolerate light frosts once established
- Protect from severe frost in colder regions
- Avoid hot, dry conditions
- Provide extra humidity during hot periods
Wind Tolerance
Whekī has moderate wind tolerance:
- Prefers sheltered locations
- Protection from strong, drying winds
- Fronds can be damaged by persistent wind
- Plant in groups for mutual protection
- Use windbreaks in exposed gardens
- More wind-tolerant than many other tree ferns
Growth Habit
Understanding Whekī's growth habit:
- Slender, black trunk up to 7 meters tall
- Distinctive suckering habit, forming groves
- Crown of dark green, arching fronds
- Slow trunk growth (5-10 cm per year)
- Moderate frond production
- Persistent dead frond bases on trunk
Garden Uses
- Feature plant in shaded gardens
- Understory planting in native forest gardens
- Restoration and revegetation projects
- Used in Māori culture for various purposes
- Symbolic in forest ecology
- Provides habitat for native species
- Stabilizes soil and supports forest ecosystems
Spring
- New fronds emerge
- Mulch and water regularly
Summer
- Monitor for pests
- Water during dry spells
Autumn
- Remove dead fronds
- Divide suckers if desired
Winter
- Protect young plants from frost
- Minimal care required
Pruning & Maintenance
Whekī (Dicksonia squarrosa) requires little pruning. Remove dead or damaged fronds at the base to maintain a tidy appearance and encourage healthy new growth. Avoid cutting into the trunk, as this can damage the plant. Pruning is best done in late winter or early spring before new fronds emerge.
Planting Guide
Whekī (Dicksonia squarrosa) prefers moist, shaded environments and thrives in rich, well-draining soil. When planting, ensure the trunk base is just above soil level. Water regularly, especially during dry periods, and mulch to retain moisture. Avoid direct sun and strong winds, which can damage fronds. Whekī is ideal for forest gardens and shaded borders.
Division of Suckers
The most reliable method for home gardeners:
- Identify healthy suckers growing from the base of an established plant
- Wait until suckers are at least 30 cm tall with several fronds
- In autumn or early spring, carefully dig around the sucker
- Cut the connection to the parent plant with a sharp spade or saw
- Ensure the sucker has its own roots
- Replant immediately in prepared soil
- Water thoroughly and keep consistently moist until established
- Protect from direct sun and wind until new growth appears
Spores
For those wanting a challenge:
- Collect fertile fronds when spore cases turn brown (usually late summer)
- Place fronds on clean paper in a warm, dry place for 1-2 days
- Collect the fine, dust-like spores that fall onto the paper
- Prepare a sterile growing medium of peat and perlite
- Sprinkle spores thinly over the surface
- Cover with glass or plastic to maintain humidity
- Keep at 18-21°C (65-70°F) in indirect light
- Mist with distilled water to maintain moisture
- Prothalli will form in 1-3 months
- Young ferns will develop in 6-12 months
- Transplant when several fronds have formed
- Growth to mature size will take many years
Trunk Transplanting
For relocating mature specimens:
- Best done in autumn or early spring
- Trim fronds to reduce transpiration
- Dig around the trunk, preserving as many roots as possible
- Carefully lift the trunk and wrap roots in damp sacking
- Replant as soon as possible at the same depth
- Water crown and soil thoroughly
- Keep consistently moist until new growth appears
- Protect from wind and direct sun during establishment
Cultural History
Whekī (Dicksonia squarrosa) was used by Māori for its fibrous trunk, which provided material for building and insulation. The plant is a common feature in New Zealand forests and is valued for its ecological role in providing habitat and moisture retention.
Pests & Diseases
Whekī (Dicksonia squarrosa) is generally hardy but can be affected by scale insects and slugs, which may damage young fronds. Fungal infections are rare but can occur in overly wet conditions. Remove affected fronds and ensure good air circulation to prevent problems.
Create a dramatic night garden feature by uplighting Whekī trunks with low-voltage garden lights. The black, textured trunks create striking silhouettes when illuminated from below, while the undersides of the fronds catch the light to create a canopy effect. This not only showcases the distinctive architectural form of these tree ferns after dark but also adds depth and dimension to evening garden spaces. Use warm-toned lights for a natural effect, and position them to highlight the contrast between the dark trunks and feathery fronds.
Cultural Significance
Traditional Uses
Whekī has been used in traditional Māori medicine and for garden design.
Learn more about the cultural significance of native trees in Cultural Plants.