Kwaowao

Microsorum pustulatum

Not Threatened

Kwaowao ( Microsorum pustulatum ), also known as Hound's Tongue Fern, is a distinctive native New Zealand fern, celebrated for its large, leathery, deeply lobed fronds and its epiphytic or lithophytic growth habit. This hardy fern is found throughout New Zealand, typically growing on tree trunks, rocks, or the forest floor in lowland and coastal forests. Its unique texture and rich green colour add a touch of primeval beauty to any landscape, making it an excellent choice for shaded, moist areas in native plant gardens or as a specimen in a fernery. Kwaowao is a resilient and aesthetically pleasing fern that showcases the diversity of New Zealand's fern flora. For related species, see the native plants index.

Kwaowao (Microsorum pustulatum) showing its large, lobed fronds growing epiphytically

Image credit: Kwaowao (Microsorum pustulatum) - Photo by Wikipedia contributors, via Wikipedia

Plant Description

Botanical Features

Kwaowao (Microsorum pustulatum), also known as Kangaroo Fern or Hound's Tongue Fern, is an evergreen fern native to Australia and New Zealand. It can be found growing as an epiphyte on rocks and trees, or terrestrially. It features glossy, leathery, bright green fronds that are evergreen. The fronds can be highly variable; juvenile fronds are often strap-like and undivided, while mature fronds are typically larger (up to 50 cm long and 15 cm wide) and deeply, but incompletely, divided into lobes (pinnatifid). The edges of the fronds may be wavy. The fern has long-creeping, fleshy rhizomes that are typically 3-11 mm in diameter, covered with appressed, blackish-brown scales. The sori (spore clusters) are usually circular or ovate, 1-5 mm in diameter, and are sunken into the frond, creating corresponding bumps on the upper surface.

Quick Facts

Table data
Scientific Name	Microsorum pustulatum
Common Name	Kwaowao, Hound's Tongue Fern
Family	Polypodiaceae
Height	Fronds up to 1 m long
Spread	Spreading, rhizomatous
Light	Partial shade to full shade
Soil	Moist, well-drained, humus-rich soils
Water Needs	Moderate to high
Frost Tolerance	Moderate
Salt Tolerance	Low
Growth Rate	Medium
Lifespan	Perennial

Climate Best Suited to

Kwaowao ( Microsorum pustulatum ) is native to New Zealand, typically found in lowland and coastal forests. It thrives in mild, temperate climates with high humidity and consistent rainfall. It prefers sheltered locations, protected from strong winds and harsh frosts. Its natural habitat includes damp forest floors, tree trunks, and rocks, indicating a preference for cool, shady, and moist conditions. It can be successfully cultivated in similar temperate regions, provided it has good drainage and protection from extreme heat or prolonged severe frosts.

Regional Suitability

Table data
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	Ideal
Invercargill	Ideal

Natural Habitat

Typical Environments

Understand the natural habitat of Kwaowao ( Microsorum pustulatum ), which is found throughout New Zealand, in lowland and coastal forests. This section details its geographical distribution, preferred environmental conditions, and the types of ecosystems where it naturally occurs.

Widespread across New Zealand, from sea level to moderate altitudes.
Found on damp forest floors, tree trunks, and rocks.
Prefers sheltered sites with good air circulation.
Thrives in partial to full shade.

Its broad habitat range highlights its adaptability and resilience, making it a fascinating subject for ecological study.

Plant Conservation

Microsorum pustulatum, commonly known as Kōwaowao or Kangaroo Fern, is generally not considered to be of significant conservation concern. It is described as "Locally common" within its preferred growing conditions in some regions and is "Abundant throughout main islands of New Zealand."

Growing Requirements

Soil Requirements

Kwaowao prefers moist, well-drained, and humus-rich soils. It naturally grows in the leaf litter of native forests or as an epiphyte on tree trunks. Amend heavy soils with compost or other organic matter to improve drainage and fertility. A neutral to slightly acidic pH is ideal. Ensure consistent moisture, especially during dry periods.

Prefers moist, well-drained, humus-rich soils.
Benefits from organic matter enrichment.
Ideal pH: neutral to slightly acidic.
Avoid waterlogged conditions.

Light Requirements

Kwaowao thrives in partial to full shade. It is sensitive to direct, harsh sunlight, which can scorch its delicate fronds. Plant it in a sheltered spot under larger trees or on the shaded side of a building where it receives dappled light or indirect sun throughout the day.

Prefers partial to full shade.
Avoid direct, harsh sunlight.
Ideal for underplanting or shaded ferneries.

Water Requirements

This fern requires consistent moisture, especially during dry periods and its establishment phase. The soil should be kept moist but not waterlogged. Regular watering is crucial for healthy frond development. Reduce watering slightly during cooler winter months.

Requires consistent moisture.
Keep soil moist, but ensure good drainage.
Water more frequently during dry spells.

Planting Guide

Best Time to Plant

The best time to plant Kwaowao is during autumn or spring, when temperatures are mild and rainfall is more consistent. This allows the fern to establish its root system before the extremes of summer heat or winter cold.

Choosing a Location

Select a site with partial to full shade and moist, well-drained, humus-rich soil. Kwaowao is ideal for planting in native plant gardens, ferneries, woodland settings, or on tree trunks and rocks. Ensure it has good air circulation and is protected from strong, persistent winds.

Planting Steps

Dig a hole twice the width of the root ball and the same depth.
Gently remove the fern from its container, being careful not to disturb the roots.
Place the fern in the hole, ensuring the top of the root ball is level with the surrounding soil.
Backfill with amended soil, firming gently around the base of the fern.
Water thoroughly immediately after planting to settle the soil.
Apply a layer of organic mulch (e.g., leaf litter) to help retain moisture and suppress weeds, keeping it away from the crown.

Initial Care

Water regularly during the first 6-12 months to help establish a strong root system. Once established, Kwaowao is reasonably low maintenance and requires less frequent watering. Protect young ferns from extreme conditions if necessary.

Ecological Role

Ecosystem Roles

The ecological importance of Kwaowao ( Microsorum pustulatum ) within its native New Zealand ecosystems is significant. It contributes to the understorey biodiversity of native forests, providing microhabitats for small invertebrates and helping to stabilize soil on the forest floor.

Contributes to understorey biodiversity.
Provides microhabitats for small invertebrates.
Helps stabilize soil on the forest floor.
Part of the rich biodiversity of native forests.

As an endemic species, it is an integral part of the unique biodiversity that has evolved in New Zealand, supporting the delicate balance of its natural habitats.

Uses & Significance

Garden Uses

Excellent for shaded native plant gardens, ferneries, and woodland settings.
Suitable for planting on tree trunks, rocks, or the forest floor to mimic its natural habitat.
Provides unique texture and visual interest.
Low maintenance once established.

Landscaping Applications

Kwaowao ( Microsorum pustulatum ) is a highly attractive and versatile fern for various landscaping applications, particularly in shaded and native gardens. Its unique texture and rich green colour make it a valuable asset.

Ideal for ferneries, woodland gardens, and shaded borders.
Excellent for planting on tree trunks or rocks to mimic its natural epiphytic habit.
Provides year-round interest with evergreen fronds.
Suitable for mass plantings or as an accent plant.

Its ability to thrive in sheltered, shaded conditions and its aesthetic appeal make it a popular choice for creating lush and beautiful native landscapes.

Seasonal Care Calendar

Spring

New fronds emerge, and this is an ideal time for planting new Kwaowao specimens or propagating from spores/division. Ensure consistent moisture and protect young plants from strong winds if necessary. A light feed with a balanced liquid fertilizer can encourage vigorous growth.

Ideal time for planting and propagation.
Ensure consistent moisture for new plants.
Light fertilization if needed.

Summer

Kwaowao is actively growing during summer. Consistent watering is crucial, especially during dry spells, to prevent wilting. Monitor for pests and diseases, though it is generally quite resilient.

Active growth.
Consistent watering is essential.
Monitor for pests and diseases.

Autumn

Growth slows as temperatures cool. This is another good time for planting, allowing roots to establish before winter. Minimal care is required for established ferns, but ensure they remain adequately hydrated.

Good time for planting.
Minimal care for established ferns.
Ensure adequate hydration.

Winter

Kwaowao is evergreen and provides year-round interest. It is moderately frost-tolerant and requires minimal care during this period. Ensure good drainage to prevent root issues in wet conditions.

Evergreen, provides year-round interest.
Protect young plants from severe frost.
Ensure good drainage.

When to Prune and How Much

Kwaowao generally requires minimal pruning. The primary reason for pruning is to remove old, dead, or damaged fronds to maintain the plant's appearance and health. Its natural growth habit is often quite attractive, so extensive pruning is rarely needed.

Remove old, dead, or damaged fronds as needed.
Light trimming to maintain shape.
Best done in late winter or early spring before new growth.
Use clean, sharp tools.

Avoid heavy pruning, as this can stress the fern. Allow it to develop its natural, graceful fronds.

How to Grow Kwaowao

Kwaowao, also known as Hound's Tongue Fern, is a distinctive native New Zealand fern, celebrated for its large, leathery, deeply lobed fronds and its epiphytic or lithophytic growth habit. This hardy fern is found throughout New Zealand, typically growing on tree trunks, rocks, or the forest floor in lowland and coastal forests. Its unique texture and rich green colour add a touch of primeval beauty to any landscape, making it an excellent choice for shaded, moist areas in native plant gardens or as a specimen in a fernery. Kwaowao is a resilient and aesthetically pleasing fern that showcases the diversity of New Zealand's fern flora. Understanding its propagation methods is key to successfully growing this delightful species.

From Spores

Difficulty: Medium

Propagating Kwaowao from spores is a rewarding method for those with patience, as it mimics the fern's natural reproductive cycle. Collect mature spores from the undersides of fronds in late summer or autumn. Sow spores on a sterile, moist substrate (e.g., peat and sand mix) in a sealed container to maintain high humidity. Keep in a warm, humid, and shaded location. Germination can take several months, forming a green film (prothalli). Once prothalli develop, transfer to a larger container and allow sporophytes to grow. Transplant young ferns once they are large enough to handle. This method allows for the production of many new plants and is ideal for large-scale restoration projects.

From Division

Difficulty: Easy

Division of established clumps is the easiest and most reliable method for propagating Kwaowao, particularly for home gardeners. This is best done in spring or autumn. Carefully dig up a mature clump. Gently separate the clump into smaller sections, ensuring each section has roots and some fronds. Replant the divisions immediately in prepared soil that is moist, well-drained, and humus-rich. Water thoroughly and keep consistently moist until new growth appears. This method is excellent for quickly expanding your stock of plants and for rejuvenating older, less vigorous clumps.

Pests & Diseases

Kwaowao is generally a robust fern and resistant to most pests and diseases. Its adaptation to diverse forest environments means it has few significant natural enemies.

Common Pests

Generally pest-free.
Occasionally, slugs and snails may damage young fronds.

Common Diseases

Highly resistant to diseases.
Root rot can occur in poorly drained, waterlogged soils.
Leaf spot diseases are rare but can occur in very humid conditions.

Good garden hygiene, proper watering, and excellent drainage are key to preventing most pest and disease issues. Healthy, well-sited plants are rarely affected by significant problems.

Cultural Significance

Microsorum pustulatum, commonly known by its Māori name Kōwaowao, holds cultural significance primarily in New Zealand. It is an integral part of the country's natural heritage, with other Māori names including pāraharaha, maratata, and raumanga.

Traditional Uses:

Food Preparation: Traditionally, the fern had practical uses, particularly in food preparation. It was used to line and cover baskets for cooking hīnau meal and tawa kernels, which was believed to impart a pleasing flavor. The young stems of the fern were also consumed, cooked as greens, and it was sometimes used to cover baskets of eels during cooking.
Medicinal: While specific traditional Māori medicinal uses for Microsorum pustulatum are not extensively documented, related Microsorum species across the Pacific have been utilized for various ailments. There is anecdotal evidence suggesting that people in New Zealand have used it medicinally, following ancestral practices.

Beyond its direct uses, Kōwaowao contributes to the cultural and ecological landscape of Aotearoa (New Zealand) through its presence in native forests. The Māori word "kōwaowao" itself also carries broader meanings, referring to "low vegetation" or "to overgrow," reflecting the fern's natural growth habit of carpeting the ground or tree trunks.

Bonus Tip

The sori (spore clusters) on the underside of the fronds are sunken into the leaf tissue, creating distinctive raised "pimples" or bulges on the upper surface. This is a great way to identify the fern, even when the sori are not visible.