Nini
Blechnum chambersii (syn. Austroblechnum chambersii)
Nini (scientific name: Blechnum chambersii, also known as Austroblechnum chambersii), commonly referred to as the Small Lance Fern, is a graceful indigenous ground fern endemic to Aotearoa New Zealand. Characterized by its compact habit and distinctive deep green, lance-shaped fronds, it is a quintessential component of New Zealand's damp forest floor and riparian ecosystems. This guide provides detailed information on its identification, ecological role, and cultivation requirements, making it an essential resource for native plant enthusiasts and restorers of native ferns. Understanding Nini highlights the delicate beauty and specialization of New Zealand's diverse understory flora.
Plant Description
Blechnum chambersii is a small to medium-sized, tufted perennial fern that typically forms compact, radiating rosettes. It possesses a stout, erect rhizome which, in older specimens, can occasionally develop into a short, trunk-like base. The foliage is strongly dimorphic, exhibiting clear differences between the sterile and fertile fronds. The sterile fronds are deep, glossy green, leathery, and lance-shaped (lanceolate), ranging from 15 cm to over 70 cm in length. These fronds are pinnatifid or once-pinnate, with numerous pairs of closely spaced, slightly overlapping pinnae that have blunt to acute tips and smooth to slightly scalloped margins.
The fertile fronds are typically shorter and more upright than the sterile ones, emerging from the center of the rosette. They have much narrower, linear pinnae that are almost entirely covered on the underside by the sori (spore clusters). Flowering (spore production) occurs throughout the year, with peak maturity reached in the summer months. This fern is often mistaken for the similar Blechnum membranaceum, but it can be distinguished by its generally larger size, broader leaf blades, and the specific arrangement of its leaflets. Its resilient, thick-textured foliage is a natural adaptation to the high-moisture but low-light niches it inhabits.
Quick Facts
| Scientific Name | Blechnum chambersii |
|---|---|
| Height | 15 - 70 cm |
| Spread | 30 - 60 cm (clump-forming) |
| Water Needs | Moderate to High (Consistently moist) |
| Light | Full shade to part shade (Prefers damp gloom) |
| Frost Tolerance | High (Hardy forest specialist) |
| Salt Tolerance | Low to Moderate (Typically found in sheltered coastal) |
| Growth Rate | Slow to Moderate |
| Lifespan | Perennial (Long-lived) |
Climate Best Suited to
Nini is exceptionally well-suited to the temperate maritime climates of New Zealand, being widespread from the subtropical north down to the cool temperate south. It flourishes in areas with high rainfall and consistent ambient humidity. Its natural range-from Te Paki to Fiordland-indicates a very high level of frost tolerance, provided it is protected by a forest canopy. It performs best in cool, shaded microclimates where it is shielded from drying winds and intense midday sun. It is particularly luxuriant in high-rainfall regions and in localized areas with limestone substrates, demonstrating a preference for stable, high-moisture environments.
Regional Suitability
| City | Climate Suitability |
|---|---|
| Auckland | Highly Suitable (Enjoys the humid forest floor) |
| Wellington | Highly Suitable (Temperate, humid, good for gullies) |
| Nelson | Highly Suitable (Flourishes in damp coastal forests) |
| Christchurch | Suitable (Requires deep shade and consistent water) |
| Invercargill | Highly Suitable (Hardy enough for the southern wet forests) |
Plant Habitat
Blechnum chambersii is a versatile indigenous fern found across the North, South, Stewart, and Chatham Islands. It occupies a variety of damp, shaded niches in lowland to montane forests. Its primary habitats include rock crevices, the base of waterfalls, and damp rock walls under forest overhangs. It is also a common component of the forest floor, particularly along stream banks in wet gullies. It thrives beneath the canopy of kauri, podocarp, broadleaved, and beech forests, as well as within mānuka and coastal scrub. It is notably luxuriant in limestone areas, where it frequently colonizes cave entrances and shaded bluffs. Its ability to grow as a low epiphyte on mossy trunks further demonstrates its specialization for moisture-rich forest environments.
Growing Requirements
Soil Requirements
Requires humus-rich, fertile, and well-drained soil that remains consistently moist.
- High organic matter (leaf mold, compost)
- Excellent moisture retention
- Tolerates thin, rocky, or limestone-based soils
- Neutral to slightly acidic pH
Light Requirements
Requires part to full shade. Prefers the damp gloom of the forest interior.
- Avoid all direct afternoon sun
- Thrives in deep shade
- Protected southern aspects are ideal
Water Requirements
High water needs. Soil should never be allowed to dry out completely.
- Consistent watering during dry periods
- Appreciates high ambient humidity (misting)
- Ideal for riparian or pond-side planting
- Maintain dampness around the rhizome
Planting and Establishing
To successfully establish Nini, choose a sheltered, fully shaded location with soil that remains naturally moist. Enrich the planting area with plenty of leaf litter or well-rotted compost. Dig a hole twice the size of the root ball, place the fern so the crown is level with the soil surface, and backfill, firming gently to remove air pockets. Water thoroughly immediately after planting and maintain high moisture levels during the first year. A thick layer of organic mulch around the base is essential to keep the root zone cool and hydrated. For the most natural effect, plant in small groups or along the edges of a shaded rock feature. Its slow to moderate growth rate means it will take a few seasons to form a lush, established clump.
Ecological Role
Blechnum chambersii is a foundational component of the damp forest floor. Its dense rosettes provide critical micro-habitats and high-humidity refuges for a wide range of native forest invertebrates and lizards. By stabilizing the soil on steep, damp banks and rock faces, it plays a role in erosion control within riparian zones. Its presence is often a key indicator of a healthy, undisturbed forest understory with stable hydrological conditions. As part of the diverse fern community, it contributes to the complex layering of New Zealand's temperate rainforests, supporting the overall resilience and biodiversity of the forest interior.
Uses & Significance
Garden Uses
Nini is a favorite among native plant enthusiasts for its tidy, compact form and lush green appearance. It is an ideal choice for shaded rockeries, fern houses, and as an underplanting for larger trees and shrubs. Its architectural fronds provide excellent textural interest in cool, moist garden niches.
- Shaded rockeries and crevices
- Native forest floor simulation
- Riparian restoration and stream banks
- Underplanting for tree ferns and large shrubs
- Containers in humid, shaded patios
Traditional & Cultural Value
Historically, Blechnum chambersii had practical significance for Māori, particularly in traditional cooking methods.
- Young fronds used in traditional hāngī cooking
- Symbol of forest floor health and vitality
- Named after the 19th-century botanist Thomas Chambers
- Component of traditional cultural landscapes
Landscaping Uses
Professional landscapers use Blechnum chambersii to create a sense of established, primeval New Zealand in shaded projects. It is an excellent tool for naturalizing damp embankments or for softening the edges of shaded pathways. Its symmetrical rosette form makes it a striking focal point when planted in groups or used to fill gaps between larger boulders in a waterfall feature. In urban gardens with limited light, Nini offers a reliable and attractive solution for creating a vibrant green groundcover that requires little maintenance once established. Its ability to thrive in limestone-rich areas offers a specialized solution for properties with alkaline soils. Mass planting can create a beautiful, uniform texture that echoes the natural forest understory.
Seasonal Care Calendar
Spring
As new fronds begin to unfurl, ensure consistent soil moisture. Apply a light dusting of balanced organic fertilizer or leaf mold to provide nutrients for the growing season.
- Monitor for new frond emergence
- Maintain soil moisture
- Light organic fertilization
Summer
This is the most critical time for moisture. Regular, deep watering is essential to prevent frond wilting. Maintain high humidity around the plant if possible.
- Regular deep irrigation
- Ensure protection from direct sun
- Provide humidity through misting
Autumn
Gradually reduce watering frequency as temperatures cool. Remove any yellowing fronds to keep the plant tidy. Prepare the site for winter dormancy.
- Reduce watering
- Tidy old or damaged fronds
- Allow natural leaf litter to collect
Winter
The plant is naturally frost-hardy but benefits from being undisturbed. Minimal watering is needed. Protect the crown from excessive debris buildup.
- Minimal care needed (extremely hardy)
- Avoid excessive winter fertilization
- Maintain barely moist soil
When to Prune and How Much
Pruning for Blechnum chambersii is minimal and primarily for maintenance and tidiness. The best time to prune is in late winter or early spring, just before the first flush of new fronds. Use sharp, sterilized shears to remove any old, dead, or yellowing sterile fronds by cutting them as close to the rhizome as possible without damaging the central crown. This encourages a healthy new growth cycle and improves air circulation through the clump. Fertile fronds that have completed their spore dispersal can also be removed if desired. Avoid heavy pruning of healthy green foliage, as this can stress the plant and reduce its overall vigor.
- Remove dead or damaged outer fronds
- Prune in early spring
- Remove spent fertile fronds in autumn
Regularly clearing the center of the rosette of large fallen leaves and debris will help prevent moisture-related rot in the crown and maintain its clean, symmetrical appearance.
How to Grow Nini
Propagating Nini (Blechnum chambersii) is a rewarding way to increase your collection of this graceful native fern. While it is a relatively slow grower, successful propagation can be achieved through both spore culture and, for established plants, careful division of the rhizome. Providing the consistently moist and shaded conditions it loves is the most critical factor for success with either method.
From Spores
Propagation from spores is a slow but fascinating process that yields a large number of plants. Spores are found on the narrow leaflets of the fertile fronds. To collect them, place a mature fertile frond in a paper envelope and leave it in a warm, dry place until the fine, dust-like spores are released. Sow the spores onto the surface of a moist, sterile seed-raising mix that is high in organic matter. Do not cover the spores with soil. Place the tray in a warm, bright greenhouse or a shaded outdoor spot and maintain high humidity by covering with a clear lid or plastic bag. Keep the surface consistently saturated with a fine mist. Germination will eventually form a green film called a prothallus, followed by tiny fern plantlets. This entire process can take 6-12 months. Once the plantlets are robust enough, transplant them into individual small pots.
- Collect mature spores from fertile fronds.
- Sow on the surface of a moist, sterile mix.
- Maintain high humidity and consistent moisture.
- Provide warm, shaded conditions.
- Wait for prothalli and then plantlets to develop.
- Transplant young ferns once they are large enough.
From Division
Division is a faster method for cloning mature plants. This is best performed in spring when the plant is starting its active growth phase. Carefully dig up a large, healthy clump and use a sharp knife or spade to separate the rhizome into smaller sections, ensuring each division has its own healthy root system and at least one or two fronds. Replant the divisions immediately into moist, organic-rich soil in a sheltered, shaded location. Water thoroughly and maintain high moisture levels until the new divisions show signs of active growth and establishment.
- Gently dig up a portion of a healthy mature clump in spring.
- Identify robust rhizome sections with roots and fronds.
- Separate carefully using a sharp, clean tool.
- Replant immediately into moist, humus-rich soil.
- Keep saturated and in deep shade until established.
Additional Methods
While seed and division are the primary methods, some success can be achieved through layering if a trailing rhizome is present. Always ensure strict hygiene by using clean tools and sterile media to prevent the introduction of pathogens. Providing a stable, humid environment for young plants is crucial for their successful establishment and long-term vitality in the garden or natural landscape. Patience is essential when propagating this specialized forest fern.
Pests & Diseases
Nini is a naturally robust species with few major pest or disease issues, particularly when grown in its ideal cool, damp forest environment. Occasionally, scale insects or mealybugs may appear on the underside of the fronds; these can be managed with a gentle application of horticultural oil. Excessive soil dryness or high heat can lead to rapid frond scorching and death. Fungal leaf spot can sometimes occur in very stagnant, humid air; improving air circulation around the plant will usually prevent this. Providing the correct environmental conditions-deep shade and consistent moisture-is the most effective way to ensure this delicate native remains healthy and pest-free.
Cultural Significance
For Māori, Nini (Blechnum chambersii) holds historical significance, particularly in traditional cooking. The young, succulent fronds were gathered and used as a lining or layer in the hāngī (earth oven), contributing a subtle flavor and providing moisture to the cooking process. Beyond its practical use, the fern is an integral part of the ecological and cultural narrative of the forest interior. Its resilience in the damp gloom of caves and waterfalls reflects the specialized and enduring nature of New Zealand's indigenous flora. Its conservation ensures that the full botanical complexity of our native bush is preserved for future generations to appreciate and learn from.
Bonus Tip
To create a truly stunning "cave entrance" effect, plant Nini in the darkest, dampest corner of your garden, perhaps near a limestone rock feature or a small dripping water element. The deep green rosettes will thrive in the low-light conditions, creating a lush, mysterious atmosphere that highlights the plant's unique architectural form. Remember to keep the area consistently wet to maintain its vibrant colour and health.
Related Plants
Explore other native New Zealand ferns that share characteristics or habitats with Nini (Blechnum chambersii), offering further insights into our remarkably diverse forest understory. These related species can provide inspiration for creating a cohesive and beautiful shade garden.
Plant Conservation
Blechnum chambersii is classified as "Not Threatened" in the New Zealand Threat Classification System. This indicates that it currently maintains stable populations throughout its extensive natural range. However, like many indigenous forest species, its long-term health depends on the preservation of our native forests and riparian corridors. Protecting these habitats from land clearing, invasive weeds, and climate-induced drying is essential. Gardeners can contribute to its conservation by using Nini in shaded restoration projects and by promoting the value of our specialized understory ferns. Sourcing plants from ethical nurseries that prioritize sustainable propagation ensures that this beautiful and robust fern continues to thrive across Aotearoa.