Polystichum richardii
Black-stemmed Fern, also known as Richard's Shield Fern, is a robust and distinctive native New Zealand fern that creates impressive displays with its substantial bipinnate fronds measuring 175-525mm long and featuring the species' most characteristic trait - striking blackish-blue primary and secondary costae (midribs) that contrast beautifully with the forest green lamina. Growing from short, erect rhizomes with moderately to densely scaly stipes reaching 100-420mm long, this adaptable species produces 11-25 pairs of primary pinnae that create elegant, shield-shaped fronds with round sori protected by distinctive peltate indusia with dark pigmented centers. Found from coastal to lowland forested areas throughout much of New Zealand's North Island and extending to the Chatham Islands, this hardy fern thrives in well-lit conditions on forested hillsides, banks, and coastal cliff faces, and has successfully adapted to urban environments where it colonizes roadside banks and cuttings, making it an excellent choice for native gardens, restoration projects, and landscaping where a substantial, architectural fern with distinctive coloring is desired. native ferns
Image credit: Black-stemmed Fern (Polystichum richardii). Wikipedia
| Scientific Name | Polystichum richardii (now Polystichum neozelandicum) |
|---|---|
| Height | 0.28-0.95 meters (including stipes and fronds) |
| Spread | 0.5-1.0 meters (clumping habit) |
| Water Needs | Moderate (forest native) |
| Light | Well-lit conditions preferred |
| Frost Tolerance | Good (coastal to lowland) |
| Salt Tolerance | Good (coastal cliff native) |
| Growth Rate | Moderate |
| Lifespan | Long-lived perennial |
Black-stemmed Fern thrives in New Zealand's temperate coastal and lowland climates, performing best in areas with reliable moisture and good light conditions. It adapts well to northern and central regions with maritime influence.
| City | Climate Suitability |
|---|---|
| Whangārei | Ideal |
| Auckland | Ideal |
| Hamilton | Ideal |
| Tauranga | Ideal |
| Rotorua | Ideal |
| Gisborne | Good |
| New Plymouth | Ideal |
| Napier | Good |
| Whanganui | Good |
| Palmerston North | Good |
| Wellington | Good |
| Nelson | Good |
| Christchurch | Moderate |
| Dunedin | Moderate |
| Invercargill | Moderate |
Black-stemmed Fern has adaptable soil preferences:
Well-lit forest conditions:
Moderate moisture needs:
Black-stemmed Fern requires minimal maintenance:
The substantial bipinnate fronds and distinctive dark costae are the main attractions and should be preserved through minimal intervention.
The best time to plant Black-stemmed Fern is during spring when active growth begins and establishment is most successful.
Choose a site with:
Water regularly during establishment and provide protection from extreme conditions. This hardy fern becomes very low-maintenance once established and will gradually form impressive clumps.
Growing from spores is highly effective:
Division is possible with established clumps:
Sometimes available from specialist native plant nurseries and fern suppliers. Easily propagated from spores and transplants well.
Black-stemmed Fern (Polystichum richardii) represents both the architectural beauty of New Zealand's shield ferns and the evolving understanding of fern taxonomy:
Today, Black-stemmed Fern serves as an excellent example of New Zealand's adaptable native flora, valued for its substantial architectural presence, distinctive coloring, and ability to thrive in both natural and human-modified environments.
Provide appropriate light conditions, good drainage, and monitor for scale insects in garden settings. This naturally hardy fern thrives when grown in conditions similar to its native forest edge habitats.
Black-stemmed Fern is perfect for creating substantial architectural displays in native gardens - the distinctive blackish-blue costae create stunning contrast against the forest green fronds, making it one of the most visually striking of New Zealand's native ferns. Unlike many ferns that need deep shade, this species thrives in well-lit forest conditions, making it ideal for forest edges, clearings, and even urban landscapes. The substantial size and robust nature make it excellent for restoration projects where you need a fern that can establish quickly and hold its own. Watch for the distinctive round sori with their dark-centered indusia - they're a key identifying feature and add to the architectural appeal.
Learn more about New Zealand's shield fern diversity in Native Ferns.
This section provides important information about plant care and cultivation practices. Understanding these aspects helps ensure successful growth and development in garden conditions.
This section provides important information about plant care and cultivation practices. Understanding these aspects helps ensure successful growth and development in garden conditions.
This section provides important information about plant care and cultivation practices. Understanding these aspects helps ensure successful growth and development in garden conditions.
This section provides important information about plant care and cultivation practices. Understanding these aspects helps ensure successful growth and development in garden conditions.
Black-stemmed tree fern plays important ecological roles in New Zealand's forest ecosystems, contributing to the distinctive layered structure that characterizes native forests while providing habitat for diverse communities of epiphytes, invertebrates, and forest organisms. The large fronds create specific microhabitats and contribute to forest moisture retention and nutrient cycling, while the sturdy trunk provides support for climbing plants and epiphytes. Its presence contributes to the ancient character and structural diversity of New Zealand's native forest ecosystems.
This section provides important information about plant care and cultivation practices. Understanding these aspects helps ensure successful growth and development in garden conditions.
This section provides important information about plant care and cultivation practices. Understanding these aspects helps ensure successful growth and development in garden conditions.
While not currently threatened, black-stemmed tree fern faces ongoing challenges from habitat modification, browsing by introduced mammals, and competition from invasive weeds that can alter forest understory conditions. The species' dependence on specific forest conditions makes it vulnerable to ecosystem changes, while its role in maintaining forest structure and biodiversity adds importance to conservation efforts. Protection focuses on maintaining healthy forest ecosystems, controlling introduced pests, managing invasive species, and preserving the complex forest conditions essential for native tree fern communities.
This plant has cultural associations in Aotearoa and is valued in restoration and gardens for ecological services; use eco‑sourced stock near natural areas.
Black-stemmed tree fern was recognized by Māori as one of the distinctive tree ferns that characterized healthy native forests, occasionally used for traditional purposes and valued as an indicator of specific forest conditions in traditional ecological knowledge. The fern's impressive size and distinctive black-stemmed trunk made it readily recognizable among forest plants, while its presence indicated mature, stable forest environments. The species continues to hold cultural significance as one of New Zealand's magnificent tree ferns and represents the ancient heritage of the country's fern-dominated forests.
This section provides important information about plant care and cultivation practices. Understanding these aspects helps ensure successful growth and development in garden conditions.
This section provides important information about plant care and cultivation practices. Understanding these aspects helps ensure successful growth and development in garden conditions.
