Hoheria populnea aka New Zealand Mallow

Hoheria populnea is moderately challenging to grow successfully. While it establishes easily from fresh seed and grows quickly, it is the most tender of the commonly cultivated Hoheria species and requires protection from severe frosts, particularly when young. The trees are typically short-lived and susceptible to Hoheria dieback syndrome, a condition that kills portions of the tree without cure. For best results, plant in a sheltered position with good drainage and avoid overly rich soil, which produces sappy growth more susceptible to frost damage.

Water newly planted lacebark trees regularly during the first 6-12 months to establish a strong root system. The plant prefers consistently moist soil and is drought-intolerant, so ensure the soil doesn't dry out completely during warm periods. Once established, mature trees require less frequent watering but still benefit from irrigation during extended dry spells. The species thrives in areas with regular rainfall and prefers a moist atmosphere.

Hoheria populnea is adaptable to most soil types, tolerating light sandy, medium loamy, and heavy clay soils. The key requirement is good drainage—the tree will not thrive in waterlogged conditions. It succeeds in both acid and alkaline soils across a wide pH range. Avoid overly rich soil, as this produces sappy growth that is more susceptible to frost damage and fungal problems.

Lacebark performs best in full sun, where it will produce the most abundant flowering. It can tolerate partial shade or dappled light but may flower less prolifically. In its native New Zealand habitat, the species naturally occurs at forest margins and in open areas, indicating a preference for good light levels. When positioning in the garden, choose a sunny spot with some protection from cold winds.

Hoheria populnea is frost-tender and prefers mild, maritime climates. It can tolerate brief frosts down to approximately -5°C to -10°C once established, but young plants need protection from severe cold. The species is rated RHS H3 (half-hardy) and is hardy in USDA zones 8-10. In colder regions, plant against a warm wall or in a sheltered position. The tree suffered significant damage in British gardens during severe winters, with many specimens killed in the December 1937 freeze.

The lacebark produces abundant white flowers approximately 25mm in diameter, appearing solitary or in clusters of 2-10 blooms. In New Zealand, flowering occurs from January to March, while in the Northern Hemisphere it blooms from August to September—typically later than related Hoheria species. The fragrant flowers are highly attractive to bees and are valued by New Zealand beekeepers as a late source of nectar and pollen. After flowering, distinctive winged fruits develop and disperse by wind.

Hoheria populnea is a fast-growing evergreen tree typically reaching 5-8 meters in height with a spread of 4-6 meters, though exceptional specimens can reach 11-12 meters in ideal conditions. Notable specimens in Irish gardens have reached 16 meters. The tree displays significant heteroblasty: juvenile plants have a compact, shrubby habit with small deeply-lobed leaves, while mature trees develop larger, broadly ovate leaves 7-14cm long with serrated margins.

Hoheria populnea is endemic to New Zealand, specifically the North Island. Its natural range extends from North Cape southward to the northern Waikato and Coromandel regions. The species inhabits coastal to montane environments, typically growing in kauri forests (Agathis australis), successional forests, and pōhutukawa-dominated coastal forest at elevations from sea level to 460 meters. It has been widely planted throughout the southern North Island, South Island, Stewart Island, and Chatham Islands, where it naturalizes freely.

Hoheria populnea is exclusively an outdoor tree, hardy in USDA zones 8-10 and RHS H3 areas. It excels in mild maritime climates and tolerates strong winds and salt spray, making it excellent for coastal gardens. In cooler regions, plant against a warm south-facing wall or in a sheltered position protected from cold northeast winds. The species is widely grown in New Zealand but mature specimens are rarely seen outside the mildest British and Irish gardens, concentrated mainly in Cornwall, Cork, and similar mild coastal areas.

Hoheria populnea can be propagated by seed, cuttings, or layering. For cuttings, take 7-10cm half-ripe wood with a heel in July/August and root in a shaded frame. Layering in April takes approximately 12 months to root. Wild seedlings often appear near mature garden specimens due to the tree's prolific self-seeding.

Prune lacebark in late winter or early spring to maintain shape and remove any dead or damaged branches. Use clean, sharp pruning tools and make cuts at a 45-degree angle just above a bud or branch junction to encourage healthy new growth. The tree generally requires minimal pruning beyond removing deadwood, but can be shaped if needed. Avoid heavy pruning, as the species can be prone to coral-spot fungus, particularly after damage or pruning wounds in cool, wet conditions.

Hoheria populnea is susceptible to Hoheria dieback syndrome, a condition that kills portions of the tree and has no known cure—this is the primary health concern for this species. The tree may suffer from coral-spot fungus, particularly after cool wet summers or following pruning wounds. Aphids and scale insects occasionally attack, feeding on sap and causing leaf yellowing; treat with horticultural oils or insecticidal soaps. On a positive note, the species shows notable resistance to honey fungus (Armillaria).

Several ornamental cultivars exist. 'Alba Variegata' features cream-white leaf margins flushed pink when young, though it defoliates easily in frost. 'Variegata' has a yellow-green central leaf zone contrasting with dark green margins. Purple-leaved forms include 'Osbornei' with purplish undersurface and blue-purple stamens, 'Foliis Purpureis' with deep purple leaf undersides, and 'Purple Shadow' with purple upper leaf surfaces that flowers in early October. Fine specimens of 'Variegata' can be seen at Abbotsbury Subtropical Gardens in the UK.

Hoheria populnea is pollinated by bees and other insects attracted to its abundant fragrant white flowers. The species is hermaphrodite, with each flower containing both male and female organs. It is particularly valued by New Zealand beekeepers as a late-season source of nectar and pollen, blooming after many other plants have finished flowering. The flowers also attract butterflies and other wildlife, making it a valuable plant for supporting pollinators in the garden.

The common name 'lacebark' refers to the distinctive inner bark, from which a very strong fiber can be extracted. This fiber has traditionally been used for making ropes, cord, and decorative elements in basketry and bonnets. The wood is white and very tough, prized by cabinetmakers and also excellent as fuel.

Hoheria populnea has limited traditional medicinal uses, rated 1 out of 5 for medicinal value. The plant has demulcent (soothing) properties and has been used as an ophthalmic remedy for treating eye complaints. However, specific preparation methods and detailed traditional uses are not well documented in available sources. The plant is not toxic and has no known hazards.