At a glance
Common name: Lacebark
Māori name: Houhere
Botanical name: Hoheria populnea A.Cunn.
Plant family: Malvaceae, the mallow family
Native status: Indigenous and endemic to New Zealand
Natural distribution: Primarily the northern North Island, although it is now planted and naturalised elsewhere
Plant parts discussed in historical use: Inner bark, leaves and flowers
Distinctive constituent: Water-soluble mucilage made up of complex polysaccharides
Traditional context: Historical records describe uses associated with skin applications, burns, digestive discomfort and respiratory complaints
Modern research: Chemical characterisation of its mucilage and investigation of its physical properties
Important distinction: Traditional use and laboratory analysis do not establish that houhere is a proven treatment for any medical condition.
Getting to know houhere
Houhere is a small to medium-sized native tree recognised by its toothed green leaves, clusters of white flowers and distinctive inner bark.
It belongs to the Malvaceae family, which also includes familiar plants such as hibiscus, okra and marshmallow. Members of this family often contain mucilage: a mixture of complex carbohydrates that absorbs water, swells and develops a soft, slippery texture.
Houhere has a particularly interesting place within this family because both its leaves and inner bark contain mucilage, while its bark has also been valued for its fine, lace-like fibres.
The tree may reach around eight metres in favourable conditions. Mature leaves are generally broad and toothed, sometimes with a darker reddish or purplish colour on the underside. Its white flowers are conspicuous when the tree is in bloom, and the fruits develop into small, dry structures with wing-like extensions.
Flowering is generally recorded from January to March, followed by fruiting from April to June, although timing can vary with local conditions.
Houhere is native to the North Island, where it occurs in coastal and lowland forest and some more elevated habitats. It is now also widely planted in gardens and restoration areas outside its original distribution.
Botanically, it is important to distinguish Hoheria populnea from other lacebarks and from plants also referred to as ribbonwood. Several related native species can look similar, particularly when young. Accurate identification matters whenever information about a particular species is being applied to its traditional or potential medicinal use.
The meaning behind the name lacebark
The common name lacebark refers to the delicate network of fibres found beneath the outer bark.
When the inner bark is separated into layers, the fibres can form a remarkably fine, net-like structure. This feature made the tree useful for traditional practical purposes well beyond its interest as a living plant.
Historical records describe the inner bark being used for weaving, bands, ties and decorative purposes. Accounts also refer to efforts to prepare bark cloth and to the use of the fibres in items associated with everyday life.
The Māori name houhere is closely associated with the tree, although historical sources also record related spellings and other regional names. The inner lace-like bark is recorded under the name repehina in ethnobotanical literature.
This combination of flexible fibres and water-responsive plant material makes houhere an interesting example of how the physical properties of a native plant can influence its usefulness.
Its value is not limited to medicinal interest. Houhere has botanical, ecological, cultural and material significance, and these aspects should be considered together when discussing its history.
Houhere in traditional knowledge
Published historical and ethnobotanical accounts describe several uses of houhere in Aotearoa. These include uses of the inner bark, leaves and flowers, with the mucilage of the bark receiving particular attention.
The available records do not all come from the same source or context. Some describe Māori knowledge and practice, while others record observations by early European writers or people living and working in the bush. They should therefore be read as historical documentation rather than as a single, uniform set of instructions followed by every Māori community.
Inner bark and mucilage
Historical records describe soaking strips of the inner bark in water until a thick, jelly-like material develops.
This material was recorded as being used externally, including in accounts involving burns and sore skin. The soft, slippery consistency helps explain its traditional association with soothing or protective applications.
The records also describe internal use in connection with digestive and respiratory complaints. Such descriptions are valuable evidence of historical practice, but they do not establish the safety, appropriate dosage or clinical effectiveness of a preparation by modern standards.
Leaves
Historical ethnobotanical sources record the use of bitter leaf infusions for stomach troubles, including an account involving bushmen. Other records refer more broadly to medicinal uses of the leaves.
These accounts should not be taken as a recommendation to prepare and drink houhere leaf infusions today. The composition, dosage, preparation quality and safety of such preparations have not been adequately established.
Burns and eye complaints
Some historical accounts describe mixtures containing houhere inner bark being applied to burns. Other reports describe bark mucilage being used around sore or weak eyes.
These are historical records, not evidence that houhere preparations are suitable for modern wound or eye care. Homemade or unverified preparations can introduce contamination and may delay appropriate treatment. In particular, plant material should not be put into the eye.
A broader cultural perspective
Rongoā Māori is more than a collection of plants and recipes. It is a living system of healing shaped by relationships with whenua, the natural environment, people and cultural knowledge.
It would be misleading to reduce that system to a list of ingredients or to assume that every historical description gives the complete context of a practice.
A respectful approach recognises the value of recorded knowledge while acknowledging that its interpretation and appropriate use require care, context and, where relevant, guidance from knowledgeable Māori practitioners.
What is mucilage?
Mucilage is a naturally occurring mixture of complex carbohydrates, also known as polysaccharides. It can absorb and retain water, producing a swollen, slippery or gel-like material.
It occurs in a variety of plants, including marshmallow (Althaea officinalis), slippery elm (Ulmus rubra), psyllium (Plantago species) and members of the mallow family.
The texture of mucilage helps explain why it has been used in traditional preparations and why it interests modern material scientists.
Depending on the plant and its chemical structure, mucilage can contribute to thickening, lubrication, water retention and the formation of soft films.
In houhere, the mucilage can be extracted from leaves and has also been associated with the inner bark in historical preparations.
It is important to separate the physical properties of mucilage from claims about medical benefits. A substance that forms a slippery coating in water may have useful material properties, but that fact alone does not show that it treats inflammation, heals wounds or relieves a particular illness in the human body.
The biological effects of a preparation depend on more than its texture. Composition, concentration, route of use, stability, contamination risk and the condition being treated all matter.
What does modern research tell us?
Scientific research into houhere has focused in part on understanding the chemical structure and behaviour of its mucilage.
This work is valuable because it moves beyond simply describing the material as a traditional remedy and begins to establish what it contains and how it behaves under controlled conditions.
However, the current evidence is primarily about composition and physical properties rather than clinical medicinal effects.
Chemical composition of houhere mucilage
A study published in 2018 investigated water-soluble mucilage extracted from Hoheria populnea leaves.
The researchers analysed its carbohydrate composition and the ways its sugar units were linked together, using techniques including chromatography and nuclear magnetic resonance spectroscopy.
They identified four principal components of the analysed mucilage: rhamnose, galactose, galacturonic acid and glucuronic acid.
The researchers found that the material had a structure predominantly associated with a type of plant polysaccharide known as rhamnogalacturonan I.
This provides a more precise understanding of houhere mucilage than a description based only on its slippery texture. Its particular arrangement of sugar units helps explain the material's physical behaviour and provides a basis for comparison with mucilages from other plants.
The findings concern the material extracted for the study. They do not mean that every traditional preparation or commercial product will have exactly the same composition.
Rheological properties: how it behaves in water
The same study examined the physical behaviour of hydrated houhere mucilage.
Rheology is the study of how materials flow and deform when force is applied. It helps explain why some substances pour easily, while others remain thick, elastic or gel-like.
The researchers found that hydrated houhere mucilage displayed pseudoplastic flow behaviour. In simple terms, it became less resistant to flow as the applied shear increased. The material also exhibited viscoelastic properties, meaning it showed characteristics associated with both fluid flow and elastic deformation.
These properties are potentially useful in the development of products requiring a thickener, suspending agent, emulsifier or binder.
The research also found that some of these physical properties were only modestly affected by changes in pH under the conditions tested.
Such findings may help guide further work on the material's suitability for particular formulations. They do not establish that consuming the mucilage provides a health benefit.
Possible applications in product development
Houhere mucilage may be of interest to researchers developing plant-derived ingredients for food or pharmaceutical formulations.
For example, a suitable polysaccharide may help a product maintain its consistency or keep ingredients evenly distributed. It may also be investigated for its ability to bind or retain water.
These are formulation functions, not medicinal outcomes. Before mucilage could be incorporated reliably into a particular product, developers would need to evaluate factors such as purity, consistency, stability, manufacturing requirements and suitability for its intended use.
The potential to use leaves rather than harvest inner bark is also worth investigating from a resource perspective, provided the material can be collected and processed sustainably.
Does research prove that houhere treats disease?
No. The study of its chemical structure and physical properties does not demonstrate that houhere treats digestive complaints, respiratory illnesses, burns or inflammatory conditions.
The historical record provides information about how the plant was used. The modern study provides information about what its mucilage contains and how the extracted material behaves.
Those are different forms of evidence.
To establish a particular medicinal benefit, researchers would need to investigate a defined preparation, test its safety and effectiveness using appropriate methods, and ultimately obtain reliable evidence relevant to people and the condition in question.
The overall picture: Houhere is a scientifically interesting source of plant mucilage with a documented history of traditional use. Modern research has clarified the chemical structure and physical properties of its leaf mucilage, but convincing clinical evidence for specific medicinal benefits remains insufficient.
Traditional preparations and contemporary products
Houhere is less familiar in commercial herbal practice than many imported medicinal plants. Its historical use and mucilage chemistry nevertheless make it worth understanding.
The form of a preparation matters because extracting, drying and processing plant material can change its composition and behaviour.
Water-based mucilage
Historical descriptions refer to soaking inner bark in water until a thick mucilage forms.
From a scientific perspective, water allows water-soluble polysaccharides to be released from plant material and hydrated. The resulting material can have a markedly different texture from the dry bark or leaves.
However, a traditional preparation should not automatically be adopted as a modern remedy. There is insufficient evidence to establish a safe and effective medicinal dose, and homemade material can vary in strength and cleanliness.
Leaf-derived mucilage
Leaves also contain mucilage and have been investigated as a source of extractable polysaccharides.
Research into leaf-derived material is particularly interesting because collecting leaves may avoid some of the damage associated with stripping a tree's inner bark.
That does not mean wild leaves should be harvested indiscriminately or consumed without guidance. Correct identification, permission to collect, growing conditions and preparation quality remain important.
Commercial ingredients and formulations
Plant mucilage can have functional value even when it is not used as an active medicinal ingredient. In food and pharmaceutical development, polysaccharides may be considered for their ability to thicken, bind or stabilise a formulation.
A product containing houhere-derived mucilage should be evaluated according to its actual purpose, manufacturing quality and ingredient information. The presence of the plant in a formulation does not establish that the product has been shown to treat a health condition.
For practitioners and consumers, it is useful to ask whether a manufacturer is referring to a traditional use, a material property demonstrated in laboratory research or a medicinal outcome demonstrated in people.
Those claims require different types of evidence.
Growing houhere
Houhere is a useful native tree to consider for suitable gardens and restoration settings within its climatic range.
It grows naturally in coastal and lowland forests and has also been recorded in more elevated habitats. Its white flowers, attractive foliage and comparatively rapid growth make it an appealing ornamental and shelter tree.
The New Zealand Plant Conservation Network describes it as an easy species to propagate from fresh seed. Young seedlings can also appear near established garden trees.
Houhere is sometimes short-lived and can be affected by a condition known as houhere dieback, which causes parts of the tree to decline. The exact cause is not fully resolved, and there is no established cure for the syndrome. Its growth habit and likely lifespan should therefore be considered when planning a garden or restoration planting.
For home gardeners, choosing a suitable sheltered location and obtaining a healthy plant from a reputable nursery are sensible starting points. In restoration projects, local provenance and the appropriateness of the species for the planting site also matter.
Growing houhere for its ecological and ornamental value is separate from harvesting it for medicinal use. A garden tree is not automatically suitable for preparing herbal products, especially if it has been sprayed or grows in contaminated soil.
Harvesting, sustainability and respect
Houhere's fine inner bark is one of its most distinctive features, but repeatedly stripping bark can injure or kill a tree. Harvesting should never be treated as a casual activity simply because the tree is relatively common in some areas.
Before collecting any material, establish who owns the land, whether permission is required and whether local rules or conservation considerations apply.
If learning about the plant within a rongoā Māori context, follow the guidance and tikanga appropriate to the people and community sharing that knowledge. The historical record alone does not provide a universal harvesting protocol.
For botanical or research purposes, it is also helpful to be clear about the part collected and how it was processed. Inner bark, leaves and flowers are not necessarily chemically interchangeable.
Responsible use of native species includes considering the health of the individual plant, the local ecosystem and the cultural significance of the knowledge associated with it.
Safety considerations
Houhere has a documented traditional history, but detailed modern safety information for medicinal preparations remains limited.
Do not assume that historical use establishes safety. The amount used, preparation method, condition of the plant and the person using it may all influence risk.
Pregnancy and breastfeeding: There is insufficient reliable safety information to recommend medicinal houhere preparations during pregnancy or breastfeeding.
Children: Traditional descriptions do not establish appropriate paediatric doses. Do not prepare or administer homemade houhere remedies to children without suitable professional guidance.
Medicines and health conditions: Information about interactions between houhere preparations and modern medicines is limited. Anyone taking regular medicines or managing a long-term condition should seek advice from a qualified health professional before considering medicinal use.
Skin applications: Do not apply homemade or unverified plant mucilage to deep, infected or serious burns, or to wounds that require medical assessment. A material that forms a gel is not automatically sterile or proven to promote healing.
Eye applications: Historical accounts describe use around sore eyes, but homemade plant material should not be put into the eye. Eye pain, redness, discharge or changes in vision warrant appropriate clinical assessment.
Internal use: There is insufficient evidence to establish a safe and effective dose for treating digestive or respiratory complaints. Avoid assuming that an infusion or mucilage prepared at home is safe to swallow.
Correct identification and cleanliness: Use of a misidentified plant or contaminated material introduces additional risks. Collection from sprayed plants, polluted sites or areas exposed to animal waste should be avoided when considering any botanical material.
Persistent symptoms, difficulty breathing, serious burns, infected wounds or changes in vision should receive appropriate medical care rather than being managed with an unverified herbal preparation.
Understanding houhere's potential
Houhere offers an opportunity to explore the relationship between traditional knowledge and modern botanical science without overstating what either can establish.
Historical sources record practical uses for the tree and its inner bark, including preparations involving mucilage. Modern chemistry has confirmed that its leaves contain complex polysaccharides with distinctive structural and physical properties.
These findings provide a foundation for further research into possible applications as a botanical ingredient. They do not yet provide strong clinical evidence for treating a medical condition.
It is also important to recognise that the tree's significance extends beyond medicinal interest. Its fibres, flowers, foliage and ecological role all contribute to its value within Aotearoa.
A thoughtful approach treats houhere as a native species with a documented history and useful scientific questions still to investigate, rather than promising health outcomes that have not been established.
In summary
Houhere (Hoheria populnea), or lacebark, is an indigenous tree of New Zealand best known for its white flowers, toothed leaves and delicate network of fibres beneath the bark.
Historical ethnobotanical accounts describe the use of its leaves and inner bark, including preparations in which mucilage was used traditionally for skin, digestive and respiratory complaints. These records help document the plant's history but should not be mistaken for modern clinical proof.
Scientific research has identified the carbohydrate components of houhere leaf mucilage and investigated its flow and elastic properties. These findings suggest potential value in the development of botanical ingredients and formulations, while leaving its medicinal effectiveness in people largely unresolved.
For anyone interested in houhere, the most responsible approach is to appreciate its botanical and cultural significance, handle native resources carefully, and distinguish clearly between recorded traditional use, demonstrated material properties and proven clinical benefits.
Sources and further reading
1. New Zealand Plant Conservation Network. Hoheria populnea — botanical description, distribution, habitat, flowering, fruiting and propagation. https://www.nzpcn.org.nz/flora/species/hoheria-populnea/ 2. Manaaki Whenua – Landcare Research, Ngā Rauropi Whakaoranga. Hoheria populnea. H. sexstylosa. Houhere. Lacebark. Historical ethnobotanical records covering Māori names, fibre, food and medicinal uses. https://rauropiwhakaoranga.landcareresearch.co.nz/names/038578df-a568-4bcd-9459-cde0ef919dab 3. Sims, I. M. et al. (2018). “Structural and rheological studies of a polysaccharide mucilage from lacebark leaves (Hoheria populnea A. Cunn.).” International Journal of Biological Macromolecules, 111, 839–847. https://pubmed.ncbi.nlm.nih.gov/29292146/ 4. Polysaccharides from New Zealand Native Plants: A Review of Their Structure, Properties, and Potential Applications. A review of the chemistry and potential material applications of polysaccharides from selected native New Zealand plants, including houhere. Plants (2019), 8(6), 163. https://pmc.ncbi.nlm.nih.gov/articles/PMC6630198/ 5. Te Ara – The Encyclopedia of New Zealand. Lacebark, houhere. Historical botanical and cultural overview of New Zealand lacebarks. https://teara.govt.nz/en/1966/lacebark-houhere This guide is educational and is not a substitute for individual medical advice or guidance from a qualified rongoā Māori practitioner.