Houhere

Botanical name: Hoheria populnea
Synonyms: Hoheria sinclairii, Hoheria populnea subsp. vulgaris var. vulgaris, Hoheria populnea subsp. vulgaris var. sinclairii, Hoheria populnea var. crataegifolia
Common name(s): Houhere, Lacebark, New Zealand mallow

About:
A fast-growing evergreen tree endemic to the northern North Island, Hoheria populnea is one of the best-known New Zealand lacebarks. It forms a small upright to spreading tree with glossy, coarsely toothed leaves and masses of attractive white flowers in late summer.

The common name lacebark refers to the remarkable lace-like network of strong fibres within the bark. These fibres were traditionally used by Māori for ropes, cordage, kete, headbands and other woven or bound items.

The species is naturally highly variable, with differences in foliage, branching and other characteristics between populations. It is also widely cultivated and readily hybridises with several other Hoheria species.

Natural habitat:
Coastal to montane forest, particularly kauri forest and successional vegetation associated with kauri.

It is also characteristic of northern coastal forest, including pōhutukawa-dominated communities.

It occurs naturally in forest margins, secondary forest and other relatively open situations and can establish readily following disturbance.

Growing environment:
Sun, Partial Shade, Coastal, Wind, Frost & Free Draining tolerant. Adaptable to a range of soils but performs best in fertile, reasonably moist, well-drained ground.

Endemic distribution:
Endemic to New Zealand and naturally restricted to the North Island.

Its natural range extends from North Cape south through Northland and Auckland to the northern Waikato and Coromandel.

It has been extensively planted outside this natural range and has naturalised in parts of the southern North Island, South Island, Stewart Island/Rakiura and Chatham Islands.

Height:
Up to approximately 8 m, occasionally taller.

Width:
Approximately 4–6 m depending on site, age and growth form.

Flowering:
January – March
Produces abundant white flowers approximately 25–30 mm across, borne both singly and in clusters of up to around 10 flowers.

Fruiting:
April – June
Produces dry, flattened, winged mericarps that are dispersed by wind.

Uses:
• Specimen tree
• Native woodland planting
• Coastal gardens
• Shelter and windbreak planting
• Temporary nurse or shelter tree
• Pollinator gardens
• Revegetation within its natural range
• Forest-margin planting
• Traditional fibre and cordage
• Kete and woven items
• Horticultural cultivars and ornamental planting

Appearance:
Growth habit:
A small, relatively soft-wooded evergreen tree, usually upright when young and becoming more spreading with maturity.

Mature trunks and branches have dark grey-brown bark, while younger growth may be dark reddish-brown to maroon.

Branches are slender, flexible and ascending, although some forms develop distinctly pendulous growth.

Unlike strongly heteroblastic Hoheria species, juvenile and adult foliage are broadly similar, although young plants generally carry much smaller leaves.

Leaves:
Leaves are leathery, glossy and usually dark green to yellow-green above. The undersides may be green or glaucous but are often attractively flushed maroon or purple, sometimes with conspicuously darker veins.

Juvenile leaves are usually around 5–30 mm long, broadly ovate, triangular or almost circular and commonly deeply serrated or lobed.

Adult leaves are much larger, generally around 50–180 mm long and 30–60 mm wide. They range from broadly ovate to ovate-lanceolate or elliptic.

The margins are characteristically coarse, with well-spaced serrated or doubly serrated teeth. Leaf tips vary considerably from rounded or blunt to sharply pointed.

Flowers:
Flowers are approximately 25–30 mm in diameter and may occur singly or in clusters of 2–10 on the same tree.

Each flower usually has five white petals approximately 10–12 mm long. The petals are obliquely oblong and are often shallowly notched at their tips.

The numerous stamens create a conspicuous centre to each flower. Some naturally occurring and cultivated forms have purple-coloured stamens.

Mature trees can flower very heavily, creating a striking display of white throughout the canopy.

Fruit:
The flowers develop into clusters of flattened, dry mericarps.

The main body of each mericarp is approximately 4.5–6.5 mm long and brown when mature. A conspicuous orange-yellow papery wing extends approximately 3–8.5 mm beyond the body and curves slightly outward.

These lightweight winged fruits are dispersed by wind.

Ecology:
Hoheria populnea is an important small tree of northern coastal and lowland forests.

Its relatively rapid growth allows it to establish in forest gaps, margins and successional vegetation, where it contributes to canopy development and provides shelter for other plants.

The abundant flowers provide pollen and nectar resources for native insects and other pollinators.

The species readily regenerates from seed and seedlings are often found around cultivated trees. This ability to naturalise means care should be taken when using it for ecological restoration outside its natural northern range.

Hoheria populnea naturally hybridises with H. sexstylosa where their distributions meet. Cultivated plants may also hybridise with H. angustifolia, H. equitum, H. ovata and H. sexstylosa.

Associated habitats:
Kauri forest, pōhutukawa coastal forest, lowland broadleaf forest, coastal forest, secondary forest, successional shrubland, forest margins and disturbed woodland.

Within ecological restoration projects, locally sourced plants should preferably be used within the species’ natural geographic range.

How to grow:
An easy and fast-growing native tree suitable for a wide range of garden situations.

Plant in full sun to partial shade in reasonably fertile, well-drained soil. Regular moisture encourages rapid growth, particularly while young, although established plants tolerate moderately dry conditions.

It responds well to pruning and can be used for shelter or as a temporary nurse tree while slower-growing native species establish.

Allow sufficient room for the crown to spread as the tree matures.

Individual trees can be relatively short-lived and may suffer from a condition commonly known as Hoheria dieback, in which branches or sections of the tree progressively die.

Propagation:
Easy from fresh seed.

Collect mature winged fruits in autumn and sow into a fine, free-draining propagation mix. Fresh seed generally germinates readily without complicated pretreatment.

Seedlings often appear naturally beneath or near mature garden trees.

For ecological planting, seed should ideally be collected from appropriate local populations because Hoheria populnea shows considerable geographic variation and readily hybridises with related species.

Cultural use:
Houhere was an important traditional source of strong fibre.

The inner bark contains a distinctive lace-like network of fibres that could be separated and processed for ropes, cordage, kete, headbands and other practical items.

The bark’s fibrous structure is also the origin of the English common name “lacebark”.

Historical accounts record experimentation with houhere fibre for producing a felt-like material comparable with some uses of aute, although this was apparently unsuccessful.

Garden value:
An excellent fast-growing native tree with attractive foliage and an impressive late-summer floral display.

The combination of glossy serrated leaves, sometimes purple-toned leaf undersides, flexible branching and masses of white flowers makes it valuable as both a specimen and shelter tree.

It is particularly appropriate for northern and coastal native gardens and restoration planting within its natural range.

Numerous horticultural forms have been selected, including plants differing in foliage, growth habit and flower characteristics. Its tendency to hybridise and naturalise should, however, be considered when planting near natural populations of other Hoheria species.