Greenhood Orchid (Pterostylis banksii) hero image

Greenhood Orchid

Pterostylis banksii

Not Threatened

This native plant, known as Greenhood Orchid (scientific name: Pterostylis banksii ), 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 Ferns .

Greenhood Orchid (Pterostylis banksii) showing its distinctive flower
Image credit: Greenhood Orchid (Pterostylis banksii) - photo by Wikipedia

Plant Description

Pterostylis banksii , commonly known as the Greenhood Orchid or Tutukiwi, is a terrestrial orchid found throughout New Zealand. It is recognized by its distinctive, hooded flower, which is typically green with white stripes. The flower resembles a praying figure, giving it a unique and fascinating appearance. The plant grows from an underground tuber, producing a rosette of leaves from which the single flower stem emerges.

Quick Facts

Pterostylis banksii quick facts
Scientific Name Pterostylis banksii
Height 10-30 cm
Spread Forms small colonies
Water Needs Moderate, prefers moist but well-drained soil
Light Partial shade to dappled light
Frost Tolerance Tolerant of light frosts
Salt Tolerance Low
Growth Rate Slow
Lifespan Perennial

Climate Best Suited to

The Greenhood Orchid is adaptable and can be found in a variety of climates, from coastal to montane regions. It prefers environments with consistent moisture and some protection from harsh conditions. It is generally found in areas with good rainfall and some tree cover.

Regional Suitability

City suitability for Greenhood Orchid
City Climate Suitability
Auckland Good
Wellington Excellent
Christchurch Good
Dunedin Good
Hamilton Good
Tauranga Good
Nelson Excellent
Queenstown Moderate

Plant Habitat

Pterostylis banksii typically grows in damp, shaded locations in native forests and scrubland. It is often found in leaf litter on the forest floor, where its tuberoids can remain dormant during dry periods. It thrives in well-drained, humus-rich soils.

Plant Conservation

While currently listed as "Not Threatened," populations of Pterostylis banksii can be impacted by habitat loss and degradation. The conservation of its native forest and scrubland habitats is important for the long-term survival of this species.

Growing Requirements

Soil Requirements

Requires a well-drained, humus-rich soil that retains some moisture. A mix of leaf mould, sand, and loam is ideal.

  • Well-drained
  • Humus-rich
  • Moisture-retentive

Light Requirements

Best grown in partial shade or dappled light, mimicking its natural forest floor habitat.

  • Partial shade
  • Dappled light

Water Requirements

Prefers consistently moist soil, especially during its growing season in spring and autumn. Reduce watering during its summer dormancy.

  • Regular moisture
  • Avoid waterlogging
  • Drier during dormancy

Planting Guide

Plant the tubers of Pterostylis banksii in autumn in a pot with a suitable orchid mix or in a shaded spot in the garden with well-drained, humus-rich soil. Plant the tuber just below the surface. Water well after planting and keep the soil moist until the leaves die back in summer.

Ecological Role

The Greenhood Orchid is pollinated by fungus gnats, which are attracted to the flower's scent. This specialized pollination is a fascinating example of co-evolution. The orchid plays a role in the forest floor ecosystem, contributing to the biodiversity of its habitat.

Uses & Significance

Garden Uses

Pterostylis banksii is a rewarding plant for orchid enthusiasts and those interested in native plants. It can be grown in pots or in a shaded rockery or native garden. Its unique flower is a conversation starter.

  • Pot cultivation
  • Shaded rockeries
  • Native gardens

The Māori name Tutukiwi means "kākā's beak," a reference to the shape of the flower. The plant was appreciated for its unique form.

  • Named for its flower shape
  • Aesthetic value

Ecological Value

The specialized pollination of the Greenhood Orchid highlights the intricate relationships within New Zealand's native ecosystems.

  • Specialized pollination
  • Indicator of ecosystem health

Cultural Significance

This plant contributes to the rich tapestry of New Zealand's native flora, known collectively as Te Wao Nui a Tāne. While specific traditional uses may vary or be less documented for some smaller species, all native plants are considered taonga (treasures) and possess a mauri (life force).

They are integral to the cultural landscape, featuring in local biodiversity and often indicating the health of the environment.

Landscaping Uses

In a garden setting, the Greenhood Orchid is best placed in a shaded, sheltered spot where its delicate beauty can be appreciated up close. It is an excellent addition to a native plant collection or a woodland garden.

Seasonal Care Calendar

Spring

Flowering occurs. Keep the soil consistently moist.

  • Flowering
  • Keep moist

Summer

The plant dies back to its underground tuber. Keep the soil relatively dry.

  • Dormancy
  • Reduce watering

Autumn

New leaves emerge. Resume regular watering.

  • New growth
  • Resume watering

Winter

The plant is actively growing. Protect from severe frosts.

  • Leaf growth
  • Protect from frost

When to Prune and How Much

Pruning requirements are generally minimal. Remove dead, damaged, or diseased plant material to keep the plant healthy and tidy. Light pruning after flowering can encourage bushier growth and prevent legginess.

Avoid hard pruning into old wood unless the species is known to regenerate well. Always use clean, sharp tools to make clean cuts and prevent the spread of disease.

How to Grow Greenhood Orchid (Tutukiwi)

From Seed

Propagation from seed is extremely difficult and requires laboratory conditions.

  1. Not recommended for home gardeners.

From Cuttings

Not applicable.

    Additional Methods

    The plant naturally forms new tubers, leading to the expansion of a colony. These can be carefully separated and replanted during the dormant summer period.

    1. Lift tubers during summer dormancy.
    2. Separate new tubers from the parent.
    3. Replant in a suitable location.

    General Propagation Tips (Seeds & Cuttings)

    Successful propagation of native New Zealand plants requires attention to detail and patience. When growing from seed, it is essential to start with fresh, viable seeds collected when they are fully mature. Clean the seeds thoroughly to remove any fleshy pulp, which can inhibit germination. Sow the seeds on the surface of a seed-raising mix that is free-draining yet moisture-retentive. A mix of peat and coarse sand or perlite often works well. Cover the seeds lightly with a fine layer of grit or sieved potting mix, or leave them uncovered if they require light to germinate. Keep the trays in a sheltered, shaded spot and maintain consistent humidity; a plastic cover can help but ensure there is adequate ventilation to prevent fungal diseases. Germination can be erratic, sometimes taking several months, so do not discard the trays too early. For vegetative propagation, semi-hardwood cuttings are often the most successful method for shrubby species. Take cuttings in late summer or early autumn, selecting healthy, non-flowering shoots. Trim them to about 10-15 cm in length, making a clean cut just below a node. Remove the lower leaves and dip the cut end in rooting hormone to encourage root development. Insert the cuttings into a propagating mix, ensuring they are firm and stable. Place them in a humid environment, such as a mist unit or a covered frame, out of direct sunlight. Rooting can take anywhere from a few weeks to several months. Once roots have formed, pot the young plants into individual containers and harden them off gradually before planting out. Division is another effective method for clump-forming plants like sedges, grasses, and lilies. This is best done in autumn or early spring when the plant is actively growing. Lift the clump carefully and tease the roots apart, using two garden forks or a sharp knife if the clump is dense. Ensure each division has a good root system and healthy shoots. Replant the divisions immediately, watering them well to settle the soil around the roots. With proper care, these new plants will establish quickly and grow into healthy specimens. By employing these methods, you can successfully expand your collection of native flora and contribute to the preservation of New Zealand's unique botanical heritage.

    Pests & Diseases

    Generally, this native plant is robust and resistant to significant pests and diseases when grown in favorable conditions. However, stress from poor drainage or drought can make it susceptible to issues.

    Monitor for common garden pests like aphids, scale insects, or slugs, particularly on young growth. Maintain good airflow around the plant to prevent fungal diseases such as mildew. In most cases, chemical intervention is not required if cultural care is adequate.

    Bonus Tip

    The Greenhood Orchid's pollination mechanism is fascinating. The labellum is touch-sensitive and springs up to temporarily trap a visiting fungus gnat, ensuring pollen is transferred.