<i>Sphaeropteris medullaris</i>(Sphaeropteris medullaris) hero image

Mamaku

Sphaeropteris medullaris

Not specified

This native plant, known as Sphaeropteris medullaris (scientific name: Sphaeropteris medullaris ), is a remarkable species endemic to New Zealand. It is characterized by its unique features, ecological role, and cultural significance. This comprehensive guide provides detailed information on its care, propagation, and importance within the New Zealand ecosystem. Understanding this plant contributes to the appreciation of our rich biodiversity and heritage, and supports conservation efforts for Browse All .

<i>Sphaeropteris medullaris</i>(Sphaeropteris medullaris) showing <i>Sphaeropteris medullaris</i>growth habit
Image credit: Mamaku (Sphaeropteris medullaris) - photo by Wikipedia contributors, via Wikipedia

Plant Description

Identification and Physical Characteristics

Sphaeropteris medullaris (syn Discover more about native grasses. Cyathea medullaris ), the mamaku or black tree fern, is New Zealandâââ€ÂšÃ‚¬ÃƒÃ‚¢Ã¢Ã¢‚¬Ã‚žÃƒÃ¢€šÃƒ‚¢s tallest tree fern, often 10-20 m with a massive, black trunk marked by distinctive hexagonal scar patterns. The arching fronds can exceed 5 m, forming an elegant shuttlecock crown; new croziers are glossy black with sparse scales.

Quick Facts

Sphaeropteris medullaris quick facts
Scientific Name Sphaeropteris medullaris
Height Up to 20 m (tallest New Zealand tree fern)
Spread 5-8 m crown spread with massive fronds
Water Needs High - requires consistent moisture and humidity
Light Partial shade to full sun (with adequate moisture)
Frost Tolerance Hardy to -3°C once established, protect young plants
Salt Tolerance Low - requires shelter from coastal winds
Growth Rate Fast - up to 50cm per year in ideal conditions
Lifespan Very long-lived (100+ years)

Climate Best Suited to

Sphaeropteris medullaris is well adapted to various New Zealand regions.

Regional Suitability

City suitability for Sphaeropteris medullaris
City Climate Suitability
Auckland High
Wellington High
Christchurch Medium

Plant Habitat

Natural Occurrence and Ecology

Common in coastal to montane forests, stream gullies and regenerating scrub throughout much of Te Ika-a-Māui (North Island) and northern/western Te Waipounamu. Typically on moist, acidic, well-drained soils with constant humidity and filtered light.

Growing Requirements

Soil Requirements

Prefers well-draining soil rich in organic matter.

  • Well-drained
  • Loamy

Light Requirements

Grows best in partial to full sun.

  • Full Sun
  • Partial Shade

Water Requirements

Requires regular watering during dry periods.

  • Regular
  • Drought tolerant once established

Planting and Establishing

Establishment Guidance

Plant Sphaeropteris medullaris in a hole twice the width of the root ball.

Proper establishment is key to long-term success. Ensure the planting hole is twice as wide as the root ball and backfill with a mix of native soil and organic compost. Initial watering should be thorough, followed by regular monitoring during the first two growing seasons to ensure the plant becomes well-anchored and resilient to local climate fluctuations.

Ecological Role

Biodiversity and Ecosystem Impact

Provides habitat and food for native fauna.

This species plays a vital role in its local ecosystem, providing essential habitat and food sources for native biodiversity. Its presence supports complex ecological interactions, contributing to the overall health and stability of the environment. By planting this native, you help maintain the intricate web of life that defines New Zealand's unique natural heritage.

Uses & Significance

Garden Uses

Ideal for rock gardens and native borders.

  • Rock gardens
  • Ground cover

Ecological Value

Supports local pollinators.

  • Birds
  • Insects

The versatility of this plant makes it a valuable addition to many New Zealand gardens. Beyond its aesthetic appeal, it offers practical benefits such as soil stabilization and shelter for smaller plants. Its historical and modern uses highlight its enduring importance in both traditional practices and contemporary landscape design, making it a thoughtful choice for any restoration or gardening project.

Landscaping Uses

Adds texture and form to modern landscapes.

In a landscape setting, this plant provides excellent structure and year-round interest. Its unique form and foliage can be used to create focal points or as a cohesive element in a larger native planting scheme. It pairs well with other New Zealand natives, allowing for the creation of diverse and resilient garden environments that reflect the natural beauty of Aotearoa.

Seasonal Care Calendar

Spring

Mulch and apply balanced fertilizer.

  • Fertilize
  • Mulch

Summer

Water deeply during dry spells.

  • Water
  • Check for pests

Autumn

Tidy up any dead foliage.

  • Prune lightly
  • Plant new specimens

Winter

Protect from heavy frosts if necessary.

  • Frost protection

When to Prune and How Much

Minimal pruning required to maintain shape.

  • Remove dead branches

Always use clean, sharp tools.

Regular maintenance through careful pruning ensures the plant remains healthy and maintains its desired shape. Focus on removing dead or diseased wood to promote better air circulation and prevent the spread of pathogens. Proper pruning techniques help the plant direct its energy toward new growth, resulting in a more robust and aesthetically pleasing specimen in your garden.

How to Grow Mamaku

Cultivating Sphaeropteris medullaris ( Sphaeropteris medullaris ) is a rewarding endeavor for any gardener interested in New Zealand's unique flora. This species can be propagated through several methods, each requiring specific conditions to ensure healthy growth and establishment. Successful propagation depends on mimicking the plant's natural environment and providing consistent care during the early stages of development.

From Seed

Propagation from seed is often the most effective way to produce a large number of Sphaeropteris medullaris plants. Seeds should be collected when they are fully mature. Freshly collected seeds generally have higher germination rates than those that have been stored for long periods.

Sow fresh seeds in a seed-raising mix.

  1. Collect seeds
  2. Sow in trays

Keep moist until germination.

From Cuttings

For those wishing to replicate specific characteristics of a parent plant, vegetative propagation via cuttings is the preferred method. This technique ensures that the new plants are genetically identical to the source. Semi-hardwood cuttings taken during the appropriate season usually yield the best results for this species.

Take semi-hardwood cuttings in late summer.

  1. Take cuttings
  2. Use rooting hormone

Additional Methods

Depending on the growth habit of Sphaeropteris medullaris , other methods such as division or layering might also be viable options. Division is particularly suitable for plants that form dense clumps or have spreading root systems, while layering can be used for species with trailing or flexible stems.

Division can be done in early spring.

  1. Divide clumps
  2. Replant immediately

Pests & Diseases

Generally resistant to major pests.

While generally resilient, maintaining optimal growing conditions is the best defense against pests and diseases. Regular monitoring allows for early detection of any issues, which can often be managed through cultural practices or organic interventions. Ensuring good air circulation and appropriate watering will significantly reduce the plant's susceptibility to common environmental stresses and pathogens.

Cultural Significance

Sphaeropteris medullaris The plant, commonly known as mamaku or black tree fern, holds significant cultural importance, particularly within Māori culture in New Zealand, and also has historical uses among Indigenous Australians. In traditional Māori culture, the drooping fronds are associated with grief and sorrow. A traditional Māori story recounts Mamaku and Toroa (the albatross) as human lovers whose constant arguing angered the gods, leading to their transformation into the tree fern and albatross, respectively. The pith from the trunk and the coiled young fronds were a traditional food source, often considered a "famine food" but also served as a "special relish at feasts." The mucilage from the sap and the pith were applied as poultices for skin conditions and to alleviate fatigued limbs. Sap from new frond stipes was used for sunburn, boils, and as a coagulant to stop bleeding. The bark of the mamaku is also used to create a traditional Māori musical instrument called a rōria (a taonga pūoro). Among Indigenous Australians, historical records indicate that the pith of the fern tree was consumed, as it contained starch similar to sago.

  • Traditional medicine
  • Crafts

Bonus Tip

Excellent for low-maintenance gardens.

For an extra boost, consider applying a thin layer of high-quality organic mulch around the base of the plant. This helps retain soil moisture, suppresses weeds, and gradually improves soil structure as it breaks down. This simple step can make a significant difference in the plant's overall vigor and resilience, especially during periods of extreme weather.

Plant Conservation

Conservation Status

Sphaeropteris medullaris , also known as mamaku or black tree fern, is a common plant found in lowland forests throughout the North Island of New Zealand and primarily in wetter coastal areas of the South Island. It is also distributed across the south-west Pacific from Fiji to Pitcairn Island. While specific IUCN conservation status is not explicitly stated, the species is described as "common" in its native range.