Tier coprosma

Botanical name: Coprosma dumosa
Synonyms: Coprosma parviflora var. dumosa, Coprosma tayloriae
Common name(s): Tier coprosma, Bush coprosma

About:
Coprosma dumosa is a bushy, densely branched shrub notable for its layered branching habit and clusters of small, thick leaves. It is widespread through much of New Zealand, especially in higher rainfall montane forests and shrublands from the Kaimai Range southwards, although it is also found in drier eastern regions of the South Island. The species is highly variable, with fruit ranging from translucent white to pale pink, yellow or bright red depending on the population.

Natural habitat:
Occurs in lowland to montane shrublands, scrub and forest, particularly in moist gullies, forest margins and upland shrublands. In southern regions it often descends to lower elevations and is also found in drier inland habitats.

Growing environment:
Prefers moist, fertile, free-draining soils in full sun to partial shade. It tolerates frost and exposed conditions, but performs best where soil moisture is reliable. In warmer regions it appreciates some shelter from intense afternoon sun.

Endemic distribution:
Endemic to New Zealand. Found in the North Island from the Kaimai Range southwards, throughout much of the South Island (though uncommon in Fiordland), and on Stewart Island/Rakiura.

Height:
1–3 m

Width:
1–3 m

Flowering:
October–November, occasionally extending into January.

Fruiting:
February–April, occasionally persisting until October.

Uses:
• Native hedging and shelter planting
• Revegetation and ecological restoration
• Understorey planting in native gardens
• Habitat and food source for birds
• Structural shrub for montane and woodland gardens

Appearance:

Growth habit:
An erect, bushy evergreen shrub with a distinctive layered or tiered branching pattern. The plant is densely leafy and often forms rounded masses of foliage.

Stems and bark:
Branches are slender yet robust, with smooth grey to grey-brown bark. Young branchlets are finely hairy, becoming smoother with age.

Leaves:
Leaves are small, thick and borne in opposite pairs or clusters along short branchlets. They are elliptic to obovate, measuring 5–13 mm long and 2–6 mm wide, and range from pale grey-green to yellow-green. The upper surface may show a faint midrib, while the underside is usually smooth with the central vein clearly visible extending to the leaf tip. In some wetter populations the upper third of the leaf margin bears minute hairs.

Flowers:
Flowers are tiny and inconspicuous, borne singly or in small clusters directly from the branchlets. Male flowers are approximately 3–4 mm long with four yellow and violet stamens. Female flowers are pale yellow with two prominent styles.

Fruit:
The fruit is a small spherical drupe, 4–5 mm in diameter, carried on a short stalk. Fruit colour is highly variable, ranging from translucent white and pale gold to pale pink or bright red. The colour, when present, is usually confined to the skin while the flesh remains clear and watery.

Ecology:
Coprosma dumosa is dioecious, with male and female flowers borne on separate plants. The fleshy drupes are eaten and dispersed by birds and other fruit-eating animals. It is an important understorey shrub in montane forests and scrub communities and provides shelter and food for native fauna.

Associated habitats:
Montane forests, subalpine scrub, shrublands, forest margins, stream gullies and lowland woodlands.

How to grow:
Grow in full sun to partial shade in fertile, well-drained soil. Plants establish readily and are hardy once mature. In warmer climates they benefit from deeper, moister soils and some protection from prolonged summer heat.

Propagation:
Easily propagated from fresh seed or semi-hardwood cuttings. Seed germinates readily when sown fresh, while cuttings root reliably when taken from actively growing shoots.

Cultural use:
As with many members of the genus, Coprosma dumosa contributes to the ecological and cultural landscapes of Aotearoa. Its berries provide seasonal food for native birds, and the species forms an important component of many natural forest and shrubland communities.

Garden value:
A versatile and hardy native shrub valued for its fine texture, attractive layered branching and colourful berries. It is excellent for native gardens, hedging, woodland plantings and restoration projects, where it provides year-round structure and wildlife value.