Epilobium pallidiflorum
Common names
tarawera, swamp willowherb
Biostatus
Native
Category
Vascular
Structural class
Herbs - Dicotyledons other than Composites
Simplified description
Robust rhizomatous perennial herb 0.25–1.4 m tall, often well branched from the base and above,
Flower colours
Violet/Purple, White
Detailed description
forming leafy stolons from near the base that become evident in relatively open sites; plants strigulose, densely so in the inflorescence, the stems strigulose all round or rarely only on the elevated lines running down from the margins of the petioles. Leaves mostly opposite, alternate in and near the inflorescence, dark green, somewhat shining, minutely strigulose along the margins and veins, the lateral veins prominent, usually 4 on each side of the midrib, narrowly lanceolate to lanceolate, attenuate at the apex, attenuate to acute at the base 30–800 × 5–13 mm, serrulate, with usually 8-28 teeth on each side subsessile. Inflorescence gracefully nodding to one side. Flowers erect. Ovaries densely strigulose, 15–30mm long, on a pedicel 4 × 10 mm long. Floral tube 1.3–2.0 × 1.5–2.8 mm, bearing a conspicuous ring of long hairs within. Sepals keeled, 4.5–8.0 × 1.3–2.0mm, strigulose. Petals 7.5–14.0 × 5.0-10.0 mm, notch 1.0-2.8 mm, deep white, often flushed with pink after fertilisation. Anthers 1.2-1.5 × 0.6-0.8 mm, cream; filaments of longer stamens 3.0-6.5 mm long, those of shorter stamens 1.5-3.5 mm, white. Style, 4.5-9.15 mm long, white, usually with scattered long hairs near the base; stigma 2.5-4.4 × 1.0-1.8 mm, white, clavate, obscurely 4-lobed at the summit, surrounded by the anthers of the longer stamens or held well above them at anthesis. Capsule 45-95 mm long, on pedicel 10-20 mm long. Seeds 0.9-1.0 × 0.4-0.45 mm, brown, papillose, obovoid, coma 5-7 mm long, white or straw-coloured, detaching readily.
Similar taxa
A distinctive species that is unlikely to be confused with any other indigenous or naturalised Epilobium present in New Zealand. Epilobium pallidiflorum is easily recognised by the tall, erect, well branched stems that may be up to 1.4 m tall; narrowly lanceolate to lanceolate leaves; a stem indumentum of even length glandular hairs; inflorescences with the buds nodding and when flowering with the white flowers mostly erect; shallowly 4-lobed stigma; conspicuously pedicellate capsules; possession of an ovary covered in appressed, strigillose eglandular hairs; and by the seeds which are 0.9-1.0 × 0.4-0.45 mm, and which lack a cellular rim, and are evenly papillose (but with papillae not in lines)
Distribution
Indigenous. New Zealand: North, South and Chatham Islands. Also Australia (New South Wales, Vicoria, South Australia, Tasmania)
Habitat
Coastal to montane (but mostly coastal and lowland) in swamps and fens or along the banks of slow flowing streams, rivers, ponds, lake margins and around lagoons. Usually in relatively open sites growing amongst sedges (Carex spp.,) rushes (Juncus spp.) and especially raupo (Typha orientialis).
Current conservation status
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2022-2023 using the New Zealand Threat Classification System (NZTCS) – more information about this can be found on the NZTCS website. This report includes replaces all previous NZTCS lists for vascular plants. Previous assessments can be found here.
- Conservation status of vascular plants in Aotearoa New Zealand, 2023. 2024. Peter J. de Lange, Jane Gosden, Shannel P. Courtney, Alexander J. Fergus, John W. Barkla, Sarah M. Beadel, Paul D. Champion, Rowan Hindmarsh-Walls, Troy Makan and Pascale Michel Department of Conservation. Source: NZTCS and licensed by DOC for reuse under the Creative Commons Attribution 4.0 International licence.
2023 | Not Threatened | Qualifiers: SO
Detailed taxonomy
Family
Endemic taxon
No
Endemic genus
No
Endemic family
No
Ecology
Flowering
November - May
Fruiting
December - June
Life cycle and dispersal
Minute pappate seeds are wind dispersed (Thorsen et al., 2009).
Propagation technique
Easily grown from fresh seed and rooted pieces. Does best when planted into a swamp or within a pot partially immersed in a pond. Although flowering plants are reasonably attractive Epilobium pallidiflorum is at best a plant for a specialist native plant grower because it is inclined to get weedy. Epilobium pallidiflorum is however, an excellent plant to establish within wetland restoration plantings where it is ideally suited to the conditions and will have room to spread.
Wetland plant indicator status rating
Information derived from the revised national wetland plant list prepared to assist councils in delineating and monitoring wetlands (Clarkson et al., 2021 Manaaki Whenua – Landcare Research Contract Report LC3975 for Hawke’s Bay Regional Council). The national plant list categorises plants by the extent to which they are found in wetlands and not ‘drylands’. The indicator status ratings are OBL (obligate wetland), FACW (facultative wetland), FAC (facultative), FACU (facultative upland), and UPL (obligate upland). If you have suggestions for the Wetland Indicator Status Rating, please contact: [Enable JavaScript to view protected content]
OBL: Obligate Wetland
Almost always is a hydrophyte, rarely in uplands (non-wetlands).
Other information
Etymology
epilobium: From the Greek epi- ‘upon’ and lobos ‘a pod’, the flowers appearing to be growing on the seed pod.
pallidiflorum: From the Latin pallidus ‘pale’ and florus ‘flower’, meaning pale-flowered
NVS code
The National Vegetation Survey (NVS) Databank is a physical archive and electronic databank containing records of over 94,000 vegetation survey plots - including data from over 19,000 permanent plots. NVS maintains a standard set of species code abbreviations that correspond to standard scientific plant names from the Ngä Tipu o Aotearoa - New Zealand Plants database.
EPIPAL
Chromosome number
2n = 36
Previous conservation statuses
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2022-2023 using the New Zealand Threat Classification System (NZTCS) – more information about this can be found on the NZTCS website. This report includes replaces all previous NZTCS lists for vascular plants. Previous assessments can be found here.
- Conservation status of vascular plants in Aotearoa New Zealand, 2023. 2024. Peter J. de Lange, Jane Gosden, Shannel P. Courtney, Alexander J. Fergus, John W. Barkla, Sarah M. Beadel, Paul D. Champion, Rowan Hindmarsh-Walls, Troy Makan and Pascale Michel Department of Conservation. Source: NZTCS and licensed by DOC for reuse under the Creative Commons Attribution 4.0 International licence.
2017 | Not Threatened | Qualifiers: SO
2012 | Not Threatened
2009 | Not Threatened
2004 | Not Threatened
Regional conservation statuses
Otago: 2024 | At Risk – Regionally Naturally Uncommon | Qualifiers: DPR, DPS, DPT, RR
The regional threat classification system leverages off the national assessments in the NZTCS, providing information relevant for the regional context. Otago conservation status information is sourced from the “Regional conservation status of indigenous vascular plants in Otago” Jarvie S et al. (2024) report.
Auckland: 2025 | At Risk – Regionally Declining | Qualifiers: DPR, DPS, DPT, PF, RR, SO
The regional threat classification system leverages off the national assessments in the NZTCS, providing information relevant for the regional context. Auckland conservation status information is sourced from the “Conservation status of vascular plant species in Tāmaki Makaurau / Auckland” Simpkins E et al. (2025) report.
Referencing and citations
References and further reading
Raven, P.H.; Raven, T.E. 1976: The genus Epilobium in Australasia. New Zealand DSIR Bulletin 216. Wellington, Government Printer.
Thorsen, M. J.; Dickinson, K. J. M.; Seddon, P. J. 2009. Seed dispersal systems in the New Zealand flora. Perspectives in Plant Ecology, Evolution and Systematics 11: 285-309
Attribution
Fact sheet prepared for NZPCN by P.J. de Lange 22 August 2011. Description adapted from Raven & Raven (1976).
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Epilobium pallidiflorum Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/epilobium-pallidiflorum/ (Date website was queried)