Wall's Coprosma
Coprosma wallii
Coprosma wallii , commonly known as Wall's Coprosma or Bloodwood, is an exceptionally rare and distinctive shrub endemic to New Zealand. It is perhaps most famous for its striking bright orange inner bark, which gives it the name Bloodwood. This species is a classic example of New Zealand's divaricating flora, forming a dense, bushy mass of interlacing branches. Found sporadically from the central North Island to the southern reaches of the South Island and Stewart Island, it is a specialist of fertile but challenging environments like alluvial frost flats and river margins. Classified as "At Risk - Declining," it is a high-priority species for conservationists and a fascinating addition to native restoration projects.
Plant Description
Coprosma wallii is a densely leafy, erect shrub or small tree that typically grows between 2 and 5 meters in height. Its most identifying feature is the bright orange inner bark, which is easily seen if a branch is snapped or the outer bark is lightly scraped. The branchlets are slender, divaricating, and often finely pubescent (hairy) when young, eventually becoming smooth and greyish.
The leaves are small, measuring 5-10 mm in length, and are dark green, leathery, and often glossy on the upper surface. They are usually held in opposite pairs or small clusters on short shoots. The plant is dioecious, meaning male and female flowers occur on separate individuals. The flowers are tiny and inconspicuous, appearing in spring. The fruit is a distinctive fleshy drupe, 3-4 mm in diameter, which is dark red to almost black (dark violet-black) when ripe. Uniquely, the fruit is often noticeably constricted between the two seeds, looking like two small globes fused together.
Quick Facts
Plant Specifications
| Scientific Name | Coprosma wallii |
|---|---|
| Family | Rubiaceae |
| Height | 2-5 metres |
| Growth Form | Dense divaricating shrub or small tree |
| Foliage | Small, dark green, leathery leaves |
| Flowers | Inconspicuous; Spring |
| Light | Full sun preferred |
| Soil | Fertile, moist, alluvial or calcareous |
| Hardiness | Very hardy; tolerates extreme frost and wind |
| Water Needs | Moderate; adaptable to wet and dry phases |
| Spread | 1.5-2.5 metres |
| Frost Tolerance | Very High |
| Salt Tolerance | Low |
| Growth Rate | Medium |
| Lifespan | Perennial |
Climate Best Suited to
Wall's Coprosma is exceptionally hardy and suited to New Zealand's cooler, more continental climates. It is a specialist of "frost flats" - areas where cold air settles and limits the growth of other trees. It thrives in Canterbury, Otago, and Southland, handling severe winter frosts and cold winds with ease. It is less suited to the humid, subtropical conditions of the far north.
Regional Suitability
| Whangārei | Suitable |
| Auckland | Suitable |
| Hamilton | Suitable |
| Rotorua | Ideal |
| Tauranga | Suitable |
| Gisborne | Suitable |
| New Plymouth | Suitable |
| Whanganui | Ideal |
| Palmerston North | Ideal |
| Napier | Ideal |
| Wellington | Ideal |
| Nelson | Ideal |
| Christchurch | Ideal |
| Dunedin | Ideal |
| Invercargill | Ideal |
| City | Climate Suitability |
|---|
Plant Habitat
This species is naturally found in high-fertility lowland to lower montane sites. It is a characteristic plant of alluvial river terraces, particularly those prone to heavy frosts or seasonal flooding. It often grows on soils derived from basaltic, andesitic, or calcareous rocks. Coprosma wallii is frequently found in "grey scrub" communities, where it associates with other small-leaved shrubs like Coprosma propinqua , Olearia species, and Melicytus alpinus . It is notable for its absence from Westland and its preference for sites where competition from broad-leaved trees is limited by environmental stress.
Plant Conservation
Wall's Coprosma is currently classified as "At Risk - Declining." The primary threats include the historical loss of its specialized alluvial habitat to intensive farming and river control works. Remaining populations are often small and fragmented, making them vulnerable to competition from invasive weeds like gorse and broom, which can prevent seedling establishment. Browsing by introduced mammals, such as cattle, goats, and possums, also severely impacts its ability to regenerate. Conservation efforts focus on fencing off known populations and incorporating the species into riparian restoration projects.
Growing Requirements
Soil Requirements
Prefers fertile, moist, and free-draining soils. It is particularly well-suited to alluvial silts and soils derived from base-rich parent materials like limestone or basalt.
- High fertility loam
- Moist but well-drained
- Tolerates occasional flooding
Light Requirements
Grows best in full sun, which maintains its tight, bushy form and encourages good branch structure. It can tolerate light, dappled shade but may become more open.
- Full sun for best density
- Open, exposed sites
- Tolerates high light levels
Water Requirements
Requires consistent moisture to establish but becomes quite resilient once mature. It can handle periods of summer drought as well as seasonal winter wetness.
- Regular watering when young
- Adaptable to wet and dry cycles
- Benefit from mulching
Planting Guide
Best Planting Practices
Plant during the cooler months of autumn or early spring. Ensure the site has been cleared of competing weeds. Dig a hole significantly larger than the root ball and enrich with compost. If the soil is naturally poor, adding a slow-release fertilizer can help. Plant at the same depth as the nursery container and water in well. A thick layer of bark mulch will help suppress weeds and retain the soil moisture that this species prefers.
Ecological Role
Environmental Benefits
As a dense, divaricating shrub, Wall's Coprosma is a powerhouse for biodiversity. It provides safe nesting sites and refuge for small native birds like the Silvereye and Grey Warbler. Its dark red berries are an important food source for birds and lizards (skinks and geckos). By stabilizing riverbanks and frost flats, it contributes to the resilience of fragile inland ecosystems.
Uses & Significance
Garden Uses
An excellent choice for gardeners looking for something unique and architectural:
- Structural focal point in modern gardens
- Tough, informal screen or hedge
- Essential component of native "grey scrub" plantings
- Riparian restoration and bird-friendly gardens
Ecological Value
High value for supporting native lizards and providing winter food for birds.
Cultural Significance
Traditional Uses and Values
While specific traditional Māori uses for Coprosma wallii are less documented than for more common species like Karamū, the Coprosma genus as a whole is significant. Divaricating shrubs were valued for their tough, wiry wood. In modern New Zealand, it is recognized as a "taonga" (treasure) of the alluvial forest remnants and a symbol of the unique biodiversity of our frost-prone plains and valleys.
Landscaping Uses
Garden Design Applications
Coprosma wallii offers an incredible texture that few other plants can match. Its fine, tangled branch structure creates a misty, cloud-like effect that looks stunning when massed together. It is particularly effective in native-themed landscapes, rock gardens, or as a backdrop for larger-leaved plants like Pseudopanax . Because it is so frost-hardy, it is a reliable choice for landscaping in difficult southern districts where other plants might fail.
Seasonal Care
Spring
Apply fertilizer; monitor for new growth; ensure weeds are cleared from base.
Summer
Water during extreme drought; check for bird activity around berries.
Autumn
Optimal time for planting; collect seeds for propagation.
Winter
Hardy to extreme frost; no protection required; enjoy the structural form.
Pruning
Pruning Techniques
Naturally forms a tight, bushy shape and requires very little pruning. It can be hard-clipped if you wish to use it as a formal hedge, or lightly trimmed to maintain a specific size. Pruning is best performed in late summer or early autumn to allow the plant to recover before winter.
How to Grow Wall's Coprosma
This species thrives in cool, open sites with sharp drainage and plenty of light. Choose a sunny position or light shade, especially in hotter districts, and avoid heavy, enriched soils that encourage soft growth. On clay, plant on a low mound and blend in grit to keep the roots dry in winter. Water young plants through their first summer, then ease back so the plant hardens and develops its characteristic tight, divaricating form.
From Seed
Propagation from seed is the most effective method. Collect the dark red berries when fully ripe. Wash the seeds to remove the fleshy pulp, as this contains inhibitors that prevent germination. Sow immediately on a tray of seed-raising mix and cover with a thin layer of grit. Keep in a cool, bright spot. Germination can be slow and may take several months, usually occurring in spring.
From Cuttings
Semi-hardwood cuttings can be taken in late summer. Select firm, current-season growth about 10-12 cm long. Dip the cut base in rooting hormone and plant in a free-draining mix of perlite and peat. Maintain high humidity and provide bottom heat if possible to increase the success rate.
Troubleshooting Common Issues
Wall's Coprosma is generally very robust. Its main issue in cultivation is root rot if planted in heavy, waterlogged clay with no drainage. Ensure the site is free-draining. Like other Coprosmas, it may occasionally host scale insects, which can be managed with horticultural oil if the infestation is severe.
Pests & Diseases
Very few major pests. It is significantly more resistant to common garden diseases than many non-native shrubs. Occasional scale insects or aphids on new growth are the most common issues, both easily controlled.
Bonus Tip
Snap a small, dead twig to see the orange "Bloodwood" colour for yourself. It is a fantastic identification trick to show visitors and adds a layer of hidden beauty to this rare native shrub.
