Coprosma chathamica
Coprosma chathamica, commonly known as Chatham Island karamū, is a species among New Zealand's native trees endemic to the Chatham Islands of New Zealand. It is a large canopy tree that can grow up to 15 meters (49 feet) tall, with a trunk diameter of up to 600 mm. It has pairs of oval leaves. Juvenile leaves are larger, measuring 45-75 mm by 20-45 mm, dark green to green, broadly ovate to ovate-oblong, with often hairy margins. Adult leaves are smaller, 20-35 mm by 15-30 mm, dark green and glossy above, paler below, and can be ovate to ovate-oblong or elliptic to oblong-elliptic, often with slightly recurved or distinctly undulose margins. The flowers are green. The ripe fruit is yellow to yellow-red or orange, obovoid, and measures approximately 9-12 mm by 9-14 mm. Coprosma chathamica is a major forest tree on the Chatham Islands, found in both coastal and inland forests. It typically grows in peaty or waterlogged soils but can also be found on limestone, schist, and basalt outcrops in free-draining areas.
| Scientific Name | Coprosma chathamica |
|---|---|
| Common Name | Chatham Islands Coprosma, Chatham Island Karamū |
| Family | Rubiaceae |
| Height | 3-6 m in cultivation |
| Spread | 2-4 m |
| Water Needs | Moderate, salt and wind tolerant |
| Light | Full sun to partial shade |
| Frost Tolerance | Hardy to -8°C |
| Salt Tolerance | High; excellent for coastal conditions |
| Growth Rate | Moderate |
| Lifespan | Long |
Chatham Islands Coprosma (Coprosma chathamica) is endemic to the Chatham Islands, where it has evolved to thrive in cool, oceanic conditions with high humidity and frequent wind. It performs best in temperate maritime climates with cool summers, mild winters, and consistent moisture. This hardy plant tolerates coastal conditions exceptionally well.
| 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 |
This plant is adaptable to a range of soil types but prefers well-drained soil with a good amount of organic matter. It can tolerate both sandy and clay soils, but good drainage is important to prevent root rot.
It grows best in full sun but will also tolerate partial shade. In very hot climates, some protection from the afternoon sun is beneficial. Its form will be more compact in a sunnier spot.
Water regularly during the first year to help the plant establish. Once mature, it is moderately drought-tolerant but will appreciate watering during long dry spells. Avoid overwatering, especially in winter.
Chatham Islands Coprosma (Coprosma chathamica) is an exceptional native tree that brings unique island character and conservation significance to New Zealand gardens. As an endemic species from the remote Chatham Islands, it represents one of the most distinctive forms in the Coprosma genus.
Known to the Moriori and later Māori as Chatham Island Karamū, this species represents the unique natural heritage of the Chatham Islands and their remarkable endemic flora.
Ecologically, Chatham Islands Coprosma plays a crucial role in the Chatham Islands' unique ecosystems, serving as both a food source for endemic bird species and a structural component of island forests.
New growth begins as temperatures warm. Apply a slow-release fertilizer suitable for native plants. This is an excellent time for planting. Monitor for consistent moisture as growth accelerates.
Water young plants regularly during dry spells. The tree's thick, glossy leaves provide excellent drought protection once established. Light pruning can be done after flowering if needed.
The distinctive translucent orange and red berries ripen, providing a spectacular display and food for birds. This is another good time for planting as conditions cool.
The tree's hardy nature shines in winter. It tolerates coastal winds and moderate frosts well. Young plants may benefit from protection in very exposed or cold locations.
Chatham Islands Coprosma (Coprosma chathamica) requires minimal pruning to maintain its natural, robust form. This hardy tree naturally develops an attractive shape with excellent wind resistance.
This tree's natural resilience and form are key features, so heavy pruning is rarely necessary or beneficial.
Plant in autumn or spring when soil conditions are mild and moisture is adequate. This allows the tree to establish strong roots before facing summer heat or winter cold.
Select a site with well-drained soil and good air circulation. This species thrives in exposed locations and coastal conditions. Allow adequate space for its mature size and spreading habit.
Dig a hole twice the width of the root ball. Incorporate compost if soil is poor. Place the plant at the same depth as in the pot. Backfill with soil, firm gently, and water thoroughly. Mulch lightly to conserve moisture.
Conservation seed propagation represents the most crucial and authentic method for growing Chatham Islands Coprosma, preserving the precious genetic heritage of this remarkable endemic species while contributing to urgent conservation efforts for one of New Zealand's most geographically restricted plants. This exceptional island endemic produces distinctive translucent orange to red berries that provide vital opportunities for maintaining genetic diversity and expanding populations of a species classified as "At Risk – Naturally Uncommon" due to its extremely limited natural distribution. The species' restriction to the remote Chatham Islands archipelago makes every successful propagation effort a valuable contribution to preserving unique evolutionary adaptations developed over millennia of island isolation. Fresh seeds from conservation sources provide the highest germination success while maintaining the authentic genetic characteristics essential for preserving this distinctive island flora that has no equivalent anywhere else in the world. Obtain seeds exclusively from reputable conservation organizations, botanical gardens, or established cultivation programs that maintain detailed records of genetic provenance and source population information essential for preserving the remaining genetic diversity of this geographically restricted species. Collect ripe berries during the natural fruiting season when they have achieved their characteristic translucent orange to red coloration and can be easily removed from branches, timing collection to ensure maximum seed viability while respecting the species' important role in providing food for endemic Chatham Islands wildlife. Process berries immediately after collection by removing all flesh through thorough washing in clean water, using gentle rubbing techniques to separate seeds from fruit material that could inhibit germination or promote fungal growth during the establishment process. Clean seeds completely by repeated washing until all fruit debris is removed, retaining the viable seeds while discarding any floating material that typically indicates poor viability or damage that could compromise successful germination. Prepare specialized germination medium that replicates the free-draining yet moisture-retentive conditions of Chatham Islands soils, using well-draining seed-raising mix enhanced with organic matter and ensuring pH levels between 6.0-7.0 that support healthy development for this unique island species. Sow fresh seeds immediately after processing, placing them on the surface of moist growing medium or covering lightly with 2-3mm of fine sand, as they benefit from light exposure during germination while requiring protection from drying out during the critical establishment period. Provide optimal environmental conditions including consistent temperatures between 15-18°C and bright, indirect light that replicates the cool, oceanic conditions of the Chatham Islands where this species has evolved specialized adaptations for island survival. Maintain careful moisture management throughout the 4-8 week germination period, ensuring growing medium remains consistently moist but never waterlogged while monitoring for the early emergence that signals successful germination of this precious genetic material. Young seedlings develop slowly while establishing the robust root systems necessary for adaptation to the challenging oceanic conditions that characterize their island home, requiring protection from environmental stress during the vulnerable establishment phase when proper care determines long-term survival success. Transplant successful seedlings with extreme care when they reach sufficient size to handle garden conditions, providing specialized growing environments that accommodate their unique island adaptations while supporting their transition to cultivation conditions that honor their conservation importance.
Island-adapted cutting propagation offers a specialized vegetative method for growing Chatham Islands Coprosma that preserves the exact genetic characteristics of exceptional parent plants while accommodating the unique challenges of propagating a species evolved for extreme island conditions. This approach is particularly valuable for maintaining superior specimens that demonstrate enhanced adaptation to cultivation conditions, exceptional ornamental characteristics, or other traits that can be preserved through careful vegetative propagation techniques specifically adapted for this challenging endemic species. The method requires advanced understanding of island plant physiology and specialized techniques developed for species adapted to harsh oceanic environments where traditional propagation methods often fail. Take semi-hardwood cuttings during late summer to early autumn when current season's growth has achieved optimal maturity for rooting while retaining the vigor necessary for successful establishment under controlled propagation environments that replicate island conditions. Select healthy, vigorous shoots from parent plants that demonstrate the best adaptation to cultivation conditions, choosing material from branches that display the characteristic thick, glossy leaves and robust growth typical of healthy Chatham Islands Coprosma development in garden settings. Cut sections 10-15cm in length with clean, sterilized secateurs, ensuring each cutting includes at least 2-3 nodes while selecting material that represents the superior characteristics of parent plants including wind tolerance, compact growth habit, and healthy foliage development. Remove lower leaves carefully to reduce transpiration stress while retaining sufficient photosynthetic capacity in upper leaves, taking special care not to damage the distinctive thick, glossy foliage that characterizes this species and provides the energy reserves necessary for successful root development. Apply specialized rooting hormone formulated for difficult-to-root native species immediately after preparation, using concentrations and formulations that have proven successful with related island endemics while ensuring even coverage of cut surfaces where new root systems must develop. Insert prepared cuttings into meticulously prepared cutting mix composed of specialized propagation medium with exceptional drainage characteristics, incorporating coarse sand, perlite, and quality organic matter to replicate the well-draining yet moisture-retentive soils of the Chatham Islands. Maintain optimal environmental conditions including high humidity (80-90%) and consistent cool temperatures around 16-18°C using specialized propagation facilities that provide the precise oceanic climate conditions essential for success with this island-adapted species. Provide bright, indirect light that supports photosynthesis without causing excessive stress, while ensuring excellent air circulation that replicates the constant oceanic breezes that characterize the natural environment of this wind-adapted species. Monitor cutting development intensively throughout the extended 8-15 week rooting period, maintaining consistent environmental conditions while watching for signs of successful root development that can be slow and variable in this challenging species. Root development occurs gradually as cuttings adapt to cultivation conditions while maintaining their island-evolved characteristics, requiring exceptional patience and specialized care throughout the establishment process that can extend over several months. This advanced method provides invaluable results for preserving specific genetic lines of this conservation-important species while contributing to breeding programs that maintain the genetic diversity essential for long-term species survival in cultivation.
Conservation cultivation provides the most comprehensive and conservation-focused approach to growing Chatham Islands Coprosma, emphasizing the preservation of this unique island endemic while contributing to broader conservation efforts for Chatham Islands ecosystems and their remarkable endemic flora. This method is essential for botanical institutions, dedicated conservation programs, and serious plant collectors seeking to maintain viable populations of this geographically restricted species that represents irreplaceable evolutionary heritage from one of the world's most isolated island groups. The approach requires expert-level knowledge of island plant ecology, specialized facilities for maintaining optimal growing conditions, and deep commitment to conservation principles that honor the species' unique evolutionary history and conservation importance. Begin by establishing specialized growing environments that replicate the cool, oceanic conditions of the Chatham Islands, including consistent cool temperatures, high humidity, excellent air circulation, and protection from temperature extremes that can stress plants adapted to stable island climates. Design cultivation programs that maintain genetic diversity through careful management of multiple genetic lines sourced from different conservation programs, ensuring that cultivated populations preserve the natural variation essential for species resilience and long-term survival potential. Source plant material exclusively through legitimate conservation channels that maintain detailed genetic records and provenance documentation, ensuring contributions to authentic conservation efforts rather than potentially compromising wild populations through unauthorized collection. Establish mother plants under optimal cultivation conditions that promote vigorous growth and reproductive success, providing the plant material necessary for ongoing propagation efforts while serving as genetic reservoirs for future conservation breeding programs. Implement specialized propagation protocols that maximize success rates while maintaining genetic integrity, using both seed and vegetative propagation methods to ensure comprehensive genetic preservation and population expansion capabilities. Monitor plant health and environmental conditions continuously using specialized equipment that tracks temperature, humidity, light levels, and air circulation to maintain the precise environmental parameters essential for long-term success with this island-adapted species. Develop integrated pest and disease management programs that prevent introduction of pathogens that could devastate small conservation populations while maintaining the plant health essential for successful reproduction and genetic preservation. Maintain detailed cultivation records that document genetic lineages, propagation success rates, plant performance, and environmental conditions to contribute to broader conservation knowledge and improve cultivation techniques for this and related island endemic species. Collaborate with conservation organizations, botanical gardens, and research institutions to coordinate conservation efforts and ensure that cultivation programs contribute effectively to broader species recovery and habitat conservation initiatives. This expert-level approach requires significant investment in specialized facilities and ongoing expertise but provides irreplaceable contributions to conserving one of New Zealand's most distinctive and geographically restricted endemic species while advancing understanding of island plant conservation and cultivation techniques.
Chatham Islands Coprosma (Coprosma chathamica) is generally very hardy with excellent natural resistance to most pests and diseases. Its island evolution has created robust natural defenses.
Success depends on providing good drainage, adequate moisture during establishment, and protection from extreme weather for young plants. Healthy trees in suitable conditions rarely experience serious problems.
Plant your Chatham Islands Coprosma where you can appreciate its translucent berries backlit by sunlight - they literally glow like jewels! This rare endemic species connects your garden to one of the most remote and special places in New Zealand. You're not just growing a tree; you're participating in the conservation of a unique island treasure.
Plants with similar habit or use can complement Chatham Islands Coprosma in mixed native plantings and habitat restoration.
Understand the highly specialized natural habitat of Chatham Islands Coprosma (Coprosma chathamica), including its endemic distribution on the Chatham Islands, specific environmental requirements, and the unique island ecosystems where it thrives. This knowledge is essential for successful cultivation and conservation.
Explore the unique ecological interactions and evolutionary adaptations of Chatham Islands Coprosma (Coprosma chathamica) within its specialized island habitat. This section provides insights into its role in island ecosystems and its remarkable adaptations to isolated island conditions.
Chatham Islands Coprosma (Coprosma chathamica) is classified as "At Risk – Naturally Uncommon," highlighting the importance of conservation efforts for this endemic species and the unique Chatham Islands ecosystems where it naturally occurs.
A comprehensive examination of the specific conditions required for successfully growing Chatham Islands Coprosma (Coprosma chathamica). This section provides advanced guidance for cultivating this remarkable endemic species with its specialized island adaptations.
Discover how Chatham Islands Coprosma (Coprosma chathamica) can be effectively integrated into specialized landscaping designs. This section offers expert advice for using this rare endemic tree in appropriate garden settings while respecting its conservation importance.
Chatham Islands Coprosma (Coprosma chathamica) plays a vital role in the unique ecosystems of the Chatham Islands, serving as both a crucial food source for endemic wildlife and an important structural component of island forest and shrubland communities.
The Chatham Islands Coprosma is a large shrub or small tree that is endemic to the Chatham Islands. It is a handsome and hardy plant, with thick, glossy, dark-green leaves. In its natural habitat, it can grow up to 15 metres tall, but is usually smaller in cultivation. It produces small, greenish-white flowers which are followed by translucent orange or red berries that are attractive to birds among New Zealand's native trees.
Chatham Islands Coprosma (Coprosma chathamica) has cultural and ecological significance in Aotearoa New Zealand. It supports native biodiversity, contributes to habitat structure, and is valued in restoration and garden plantings. Within mātauranga Māori, native plants like this help sustain the health of the ngahere (forest) and local ecosystems.
