Karamū
Botanical name: Coprosma lucida
Synonyms: Coprosma australis, Ronabea australis, Coprosma grandifolia
Common name(s): Karamū, Shining karamū, Kāramuramu, Kakaramu
About:
Karamū is a fast-growing shrub or small tree renowned for its glossy green foliage and bright orange-red fruit. It is one of New Zealand’s larger-leaved coprosmas and is easily recognised by its shiny leaves with a strongly raised midrib visible on both surfaces. Common throughout much of New Zealand, it is an important component of forest margins and regenerating native bush, where it provides food and shelter for wildlife.
Natural habitat:
Occurs naturally in coastal to montane forests, forest margins, shrublands and regenerating bush. It is especially common as an understorey or sub-canopy species in mixed podocarp-hardwood forests and kauri forests.
Growing environment:
Prefers moist, fertile, well-drained soils in full sun to semi-shade. Tolerates shade, coastal conditions and light frost. Also grows naturally in geothermal areas and can establish readily after disturbance.
Endemic distribution:
Endemic to New Zealand. Found throughout the North and South Islands and on several offshore islands, extending south to Big South Cape Island. It is uncommon on Stewart Island due to browsing pressure from deer.
Height:
5–6 m
Width:
2–4 m
Flowering:
Spring to early summer.
Fruiting:
Fruit develops slowly over approximately 17 months, with ripe fruit present mainly from autumn through winter. Plants often carry flowers and fruit simultaneously.
Uses:
• Revegetation and ecological restoration
• Shelter planting
• Forest edge and understorey planting
• Bird-attracting gardens
• Traditional yellow dye source from the bark
Appearance:
Growth habit:
A vigorous shrub or small tree with stout branches and an upright to spreading habit. Young stems are bright green and become brown and woody with age.
Trunk and branches:
Branches are thick and smooth, with green tissue visible beneath the bark. The roots and inner bark are bright yellow due to naturally occurring anthraquinone compounds.
Leaves:
Leaves are glossy dark green above and paler beneath, arranged in opposite pairs. They are elliptic to broadly elliptic, 120–170 mm long and 30–50 mm wide, tapering gradually to both the tip and leaf stalk. The midrib is strongly raised and can be felt on both upper and lower surfaces. Small domatia (tiny pits) occur beneath the leaves where the lateral veins join the midrib. The margins are sometimes slightly wavy.
Between the leaf stalks sits a small triangular green stipule tipped with fine hairs, lacking the black point seen in the similar Coprosma robusta.
Flowers:
Plants are usually dioecious, with male and female flowers on separate plants, although occasional monoecious plants occur. The flowers are small, green to white, and borne in clusters arising from the leaf axils.
Fruit:
Fruit are produced in small open clusters on obvious stalks. The drupes are oblong, fleshy and orange-red to bright red when ripe, each containing two seeds.
Ecology:
Karamū is an important early successional species that quickly colonises disturbed sites, forest margins and canopy gaps. The fleshy fruits are eaten and dispersed by birds, making the species an important food source for native wildlife. The leaves provide habitat for beneficial mites within their domatia, while birds, insects and other animals use the shrub for shelter.
Associated habitats:
Coastal forest, podocarp-hardwood forest, kauri forest, regenerating scrub, geothermal shrubland, forest margins and montane forest.
How to grow:
Grow in full sun to partial shade in moist, fertile, free-draining soil. It is fast growing, tolerant of a wide range of conditions and suitable for shelter planting, revegetation and native gardens. Once established it is hardy and relatively low maintenance.
Propagation:
Very easy to grow from fresh seed. Seed germinates readily after cleaning the fruit pulp away. Semi-hardwood cuttings can also be rooted successfully.
Cultural use:
Māori used the yellow inner bark as a natural dye source. The abundance and size of the fruit were also traditionally used as indicators of forest health and seasonal productivity.
Garden value:
Karamū is one of the most useful native shrubs for restoration and home gardens. Its glossy foliage, colourful fruit and rapid growth make it ideal for creating shelter, attracting birds and establishing native vegetation. Its tolerance of shade and ability to colonise disturbed sites make it particularly valuable in ecological restoration projects.