Crown Fern (Piupiu)

Blechnum discolor

Not Threatened

Blechnum discolor, commonly known as Crown Fern or Piupiu in te reo Māori, is a distinctive and attractive native fern of New Zealand. It forms a striking crown of arching fronds that emerge from a central point, creating a fountain-like appearance. With its elegant form and adaptability to shaded environments, Crown Fern is both an important component of native forest understories and a species of notable ecological significance in New Zealand's forest ecosystems.

Crown Fern (Blechnum discolor) showing its distinctive crown-like formation

Image credit: Wikipedia

Quick Facts

Height	0.5-1 meter
Water Needs	Moderate to high
Light	Shade to partial shade
Frost Tolerance	Moderate
Growth Rate	Slow to moderate
Lifespan	Long-lived perennial

Climate Best Suited To

Crown Fern is native to the forests of New Zealand, where it thrives in cool, moist, shaded environments. It is found throughout the country in suitable habitats, particularly in damp gullies and forest understories. It prefers areas with consistent moisture and protection from direct sunlight and drying winds.

Regional Suitability

City	Climate Suitability
Whangārei	Moderate
Auckland	Moderate
Hamilton	Ideal
Tauranga	Moderate
Rotorua	Ideal
Gisborne	Moderate
New Plymouth	Ideal
Napier	Challenging
Whanganui	Moderate
Palmerston North	Ideal
Wellington	Ideal
Nelson	Ideal
Christchurch	Moderate
Dunedin	Ideal
Invercargill	Ideal

Growing Requirements

Soil Requirements

Crown Fern 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 fern prefers shaded conditions:

Deep to dappled shade
Protection from direct sunlight, especially midday sun
Morning sun tolerated in cooler regions
Ideal under canopy of trees or larger shrubs
Can tolerate more light if soil remains consistently moist
Avoid hot, exposed sites

Water Requirements

Consistent moisture is key for Crown Fern:

Regular watering to maintain even soil moisture
Never allow soil to dry out completely
Reduce frequency in winter but don't let soil dry out
Benefits from misting in dry conditions
Mulch to help retain soil moisture
Good drainage to prevent waterlogging

Temperature Tolerance

Crown Fern has the following temperature preferences:

Prefers cool to moderate temperatures
Ideal growing range: 10-24°C (50-75°F)
Can tolerate light frosts once established
Protect from severe frost in colder regions
Dislikes hot, dry conditions
Provide extra humidity during hot periods

Crown Fern's ecological significance is evident in its role as a key understory species. Its presence indicates a healthy forest ecosystem, and its growth requirements reflect its ecological significance in maintaining forest moisture levels and providing habitat for small forest creatures.

Uses & Significance

Garden Uses

Shaded woodland gardens
Native ferneries
Understory planting
Natural areas
Container growing in shade

Cultural Significance

Traditional Māori uses for bedding
Seasonal indicator plant
Part of forest ecosystem
Historical fern collection specimen

Ecological Value

Forest understory species
Habitat for invertebrates
Soil stabilization
Moisture retention in forest floor
Indicator of forest health

Seasonal Care Calendar

Spring

Remove any winter-damaged fronds
Apply slow-release fertilizer if needed
Divide overgrown clumps
Plant new specimens
Monitor for pests
Ensure adequate moisture as growth resumes

Summer

Water regularly during dry periods
Mist fronds in hot weather
Monitor for signs of heat stress
Remove any damaged or yellowing fronds
Maintain mulch layer

Autumn

Ideal time for planting
Clean up fallen debris
Apply fresh mulch
Reduce watering as temperatures cool
Monitor for slug damage

Winter

Minimal care needed
Protect from severe frost
Remove damaged fronds
Maintain consistent moisture
Plan for spring division if needed

When to Prune and How Much

Crown Fern requires minimal pruning but benefits from regular maintenance:

Remove dead, damaged, or yellowing fronds at any time
Cut old fronds back to the base in late winter/early spring
Use clean, sharp tools to prevent disease spread
Avoid cutting new fronds that are still unfurling
Remove any unwanted plantlets that appear

Note: Always sterilize pruning tools between plants to prevent the spread of disease. Make clean cuts close to the base of the frond to maintain plant health and appearance.

Planting Guide

When to Plant

The best time to plant Crown Fern is during autumn or spring when temperatures are mild and rainfall is more reliable. This gives the plant time to establish before extreme weather conditions.

Site Selection

Choose a location that mimics the fern's natural habitat:

Shaded woodland gardens or ferneries
Under the canopy of trees or large shrubs
North-facing slopes (in Southern Hemisphere)
Protected gullies or alongside streams
Areas protected from strong winds
Avoid hot, exposed sites

Planting Steps

Prepare the planting area by incorporating plenty of organic matter
Dig a hole twice as wide as the root ball
Position the plant so the crown is level with the soil surface
Backfill with soil, firming gently
Water thoroughly after planting
Apply a layer of mulch, keeping it away from the crown

Initial Care

Water regularly during the first growing season, especially during dry periods. Protect from strong winds and direct sun until established.

Propagation Methods

Division

Difficulty: Easy to Moderate

The most reliable method for home gardeners:

Divide established plants in early spring or autumn
Carefully dig up the entire plant
Use a sharp knife or spade to separate the crown into sections
Ensure each division has both roots and fronds
Replant divisions immediately at the same depth as before
Water thoroughly and keep consistently moist until established
Protect new divisions from direct sun and wind

Spores

Difficulty: Challenging

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

Cultural History

Crown Fern has a place in New Zealand's natural and cultural heritage:

Traditional Māori Uses

Known as "piupiu" or "petipeti" in te reo Māori
Fronds sometimes used for bedding material
Used as a calendar plant, with new growth indicating seasonal changes
Occasionally used for medicinal purposes
Provided shelter for ground-dwelling insects that were food sources

Ecological Significance

Important component of native forest understories
Provides habitat for small invertebrates
Contributes to forest floor biodiversity
Helps prevent soil erosion on forest floors
Indicator species for healthy forest ecosystems

European Settlement Impact

Collected by early European botanists
Habitat reduced through forest clearance
Included in Victorian-era fern collections
Specimens sent to European botanical gardens

Contemporary Significance

Today, Crown Fern is valued both for its ecological role in native forests and as an ornamental plant in gardens. Its distinctive crown-like form makes it a popular choice for shaded gardens and native plantings. Conservation efforts include preserving its natural habitat in protected forest areas and using it in restoration projects to rebuild native forest understories.

Pests & Diseases

Common Pests

Slugs and Snails: Often damage new fronds. Control with organic baits, copper tape, or beer traps.
Scale Insects: May appear on fronds as small bumps. Remove with cotton swab dipped in alcohol or use horticultural oil.
Caterpillars: Occasionally feed on fronds. Hand-pick or use organic Bacillus thuringiensis spray if infestation is severe.
Mealybugs: Sometimes infest the crown and base of fronds. Treat with insecticidal soap or neem oil.

Common Diseases

Root Rot: Caused by overwatering or poor drainage. Ensure well-draining soil and avoid waterlogged conditions.
Crown Rot: Often results from water sitting in the crown. Avoid overhead watering and ensure good air circulation.
Fungal Leaf Spots: Various fungi can cause spotting on fronds. Improve air circulation and avoid overhead watering.
Rust: Appears as orange or brown spots on fronds. Remove affected fronds and improve air circulation.

Environmental Issues

Desiccation: Low humidity causes frond edges to brown and curl. Increase humidity with misting or mulching.
Sunburn: Direct sunlight causes yellowing and browning of fronds. Move to a more shaded location.
Frost Damage: Severe frosts can damage fronds. Protect with frost cloth during cold snaps.
Wind Damage: Strong winds can tatter fronds. Plant in sheltered locations or provide windbreaks.

Crown Fern is generally resilient to pests and diseases when grown in appropriate conditions. Good cultural practices including proper spacing, appropriate watering, and good air circulation will prevent most problems. This fern is more susceptible to environmental stress than pest or disease issues, so focus on providing the right growing conditions.

Bonus Tip

Create a stunning visual effect by planting Crown Fern in a circular pattern around the base of a native tree or large shrub. The radiating crowns of the ferns echo the circular pattern, creating a natural mandala effect when viewed from above. This arrangement not only looks beautiful but also mimics the way these ferns naturally grow in forest settings. For added interest, intersperse with native ground covers like Pratia angulata (Panakenake) with its tiny white flowers.