Swamp Coprosma
Botanical name: Coprosma tenuicaulis
Synonyms: Coprosma tenuicaulis var. major
Common name(s): Swamp Coprosma, Hukihuki
About:
Coprosma tenuicaulis is an elegant wetland shrub distinguished by its fine interlacing branches, slender twiggy growth and small rounded leaves with pale central markings. It is one of New Zealand’s most characteristic swamp shrubs and is commonly found growing around wetlands, bogs and lake margins. The dark purple-black fruit provides an important food source for native birds.
Natural habitat:
Occurs naturally in swamps, bogs, wetlands, poorly drained shrublands, riparian forests and lake margins. It is most commonly found in lowland habitats but occasionally extends into montane environments.
Growing environment:
Prefers moist to waterlogged soils but adapts readily to a wide range of conditions. Grows well in full sun or partial shade and tolerates both poorly drained and free-draining soils.
Endemic distribution:
Endemic to New Zealand. Found throughout much of the North and South Islands from Kaitaia south to approximately Okarito.
Height:
1–3 m
Width:
1–2.5 m
Flowering:
July–October
Fruiting:
March–May
Uses:
• Wetland restoration planting
• Riparian planting
• Wildlife habitat creation
• Native shelter planting
• Pond and lake margin planting
• Ecological restoration projects
Appearance:
Growth habit:
A bushy evergreen shrub with slender interlacing branches and a finely textured appearance. The growth habit is often subdivaricating, creating a dense but delicate framework.
Trunk and branches:
Branches are slender and flexible, with numerous fine branchlets. Young stems are covered in fine hairs and often form intricate interwoven networks.
Leaves:
Leaves are borne in opposite pairs on short flattened winged stalks. They are rounded to spoon-shaped, 8–13 mm long and 8–10 mm wide, with a slightly leathery texture. The upper surface is typically marked by a pale central blotch surrounded by darker green margins. Fine vein reticulations are visible on both leaf surfaces. Between the leaf bases are small stipules bearing a conspicuous tuft of hairs.
Flowers:
Flowers are small, greenish-white and wind-pollinated. Male flowers occur in clusters of three to six, while female flowers are solitary or borne in small clusters. Male and female flowers are produced on separate plants.
Fruit:
The fruit is a small fleshy globose drupe, 3–4 mm in diameter. The skin is dark reddish-black to black when ripe, while the flesh is deep purple. Fruits are produced in generous clusters and are attractive to birds.
Ecology:
The fruit is dispersed by birds (frugivory), which consume the berries and distribute the seed throughout wetland habitats. The dense branching structure provides shelter for insects and small birds, while the fruit offers a valuable seasonal food source.
Associated habitats:
Swamps, bogs, wet shrublands, lake margins, wet forest margins, riparian forest, peat wetlands, floodplains and poorly drained lowland forest.
How to grow:
Plant in full sun or partial shade in moist soil. Although naturally associated with wetlands, it is surprisingly adaptable and can be grown successfully in both damp and reasonably well-drained garden soils. It benefits from regular moisture during establishment.
Propagation:
Easy from fresh seed and semi-hardwood cuttings. Seed germinates readily after the fruit pulp is removed, while cuttings strike reliably under suitable conditions.
Cultural use:
Swamp coprosma contributes to the ecological health of New Zealand wetlands and provides important habitat and food resources for native wildlife. It forms part of the diverse native flora associated with traditional Māori landscapes.
Garden value:
Swamp coprosma is highly valued for its graceful twiggy habit, attractive mottled foliage and glossy black fruit. Its adaptability, fine texture and suitability for wet areas make it an excellent choice for wetland restoration, pond margins, native gardens and ecological plantings.