Epilobium pedunculare
Common names
willowherb
Biostatus
Native – Endemic taxon
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
Category
Vascular
Structural class
Herbs - Dicotyledons other than Composites
Flower colours
White
Detailed description
Creeping perennial herb forming diffuse mats up to 0.5 m diameter, stems prostrate, rooting at nodes; strigulose or with short erect hairs on lines decurrent from the margins of the petioles. Leaves opposite, green to coppery, dull to ± coppery, the lateral veins inconspicuous, usually 2-3 on each side of the midrib; petioles 0-5 mm long; lamina 2.5-14 × 2.5-15 mm, very broadly ovate to orbicular, subacute to rounded at the apex, obtuse to truncate at the base, serrate with 3-14 teeth on each side. Flowers erect arising from the axils of ordinary leaves with the stems continuing to grow betond them. Ovaries 8-25 mm, glabrous; on a pedicel 3-50 mm long. Floral tube 0.7-0.9 × 0.9-1.5 mm. Sepals 1.7-3.5 × 0.6-1.0 mm, prominent in bud and opened flowers, not keeled, glabrous, with much extended, light-coloured apices. Petals 3.0-5.0 × 1.9-2.6 mm, notch 0.6-1.0 mm deep, white (rarely pink). Stamen filaments white of two types: long (0.5-2.0 mm long) and short (0.6-1.0 mm long), Anthers 0.2-0.25 × 0.1-0.15 mm, yellow. Style 0.7-1.8 mm long, white; stigma 1.2-1.9 x 0.5-0.9 mm, white, clavate, surrounded by the anthers at anthesis. Capsule 20-50 mm long, subglabrous to glabrous, on a pedicel 45-100 mm long. Seeds 0.6-1.0 mm long, orange-brown, narrowly elliptic, narrowly obovate-elliptic or narrowly oblong-obovate, finely reticulate-mammillate; coma 5-7 mm long, white, caducous.
Similar taxa
Epilobium pedunculare is a very distinctive species that is perhaps most similar to E. rotundifolium with which it may share a common ancestry (see comments by Raven & Raven 1976). From Epilobium rotundifolium and indeed other epilobia, E. pedunculare is distinguished by the opposite, sharply serrated leaves (each bearing 5-14 teeth on either side); by the creeping stems which root at the nodes and grow beyond the flowering portion; by the stem indumentum which is not evenly pubescent, bearing instead short, erect, bristly hairs; flowers which are borne in leaf axils, floral tube 0.7-0.9 × 0.9-1.5 mm; white (rarely pink) petals, and seends that lack an obvious cellular rim. Large forms of E. pedunculare (i.e those that match the type of E. linnaeoides) unless flowering can be confused with E. rotundifolium, especially as the young growth is often tinged coppery.
Distribution
Endemic. New Zealand: North (but scarce north of Auckland), South, Stewart, Antipodes, Auckland, Campbell, Macquarie Islands. Naturalised in Great Britain & Ireland.
Habitat
Coastal to montane. Usually in forest especially on damp lightly shaded and sparsely vegetated banks and along shaded stream sides. Also found in damp sites within tussock grassland, and amongst or growing from the bases of sedges (Carex spp.) in swamps.
Detailed taxonomy
Genus
Family
Synonyms
Epilobium nummulariifolium var. pedunculare (A.Cunn.) Hook.f., Epilobium caespitosum Hausskn., Epilobium linnaeoides Hook.f.
Taxonomic notes
Raven & Raven (1976) treated Epilobium linnaeoides Hook.f. as part of E. pedunculare. Epilobium linnaeoides was described from specimens collected from Campbell Island and is the typical form of E. pedunculare sensu Raven & Raven (1976) found in the southern North Island, South, Stewart, Chatham and subantarctic Islands. Some botanist regard E. linnaeoides as a distinct species in its own right noting that in some parts of the country it grows sympatrically (and more rarely syntopically) with E. pedunculare. However, in this particular case as Raven & Raven (1976) point out E. linnaeoides differs from E. pedunculare by its larger size and overall more robust growth habit. There are no other significant differences, on which basis it seems that the retention of two species as advocated by some botanists has little to commend it. Further, plants matching the description of E. linnaeoides collected from the Chatham Islands and cultivated in Auckland over a period of some 12 months reverted in size to the “typical” form of E. pedunculare, while seed collected from the Chatham Islands also reverted. Under these circumstances, and pending further study it seems better to retain the circumscription of E. pedunculare offered by Raven & Raven (1976).
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Ecology
Flowering
September - May
Fruiting
October - July
Life cycle and dispersal
Minute pappate seeds are wind dispersed (Thorsen et al., 2009).
Propagation technique
Easily grown from fresh seed and rooted pieces. Not as invasive as other species. A rather attractive ground cover for a damp, shaded site in most gardens and soil types
Other information
Etymology
epilobium: From the Greek epi- ‘upon’ and lobos ‘a pod’, the flowers appearing to be growing on the seed pod.
pedunculare: Flowers stalked
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.
EPIPED
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
2012 | Not Threatened
2009 | Not Threatened
2004 | Not Threatened
Regional conservation statuses
Auckland: 2025 | Regionally Threatened – Regionally Endangered | Qualifiers: DPR, DPS, DPT, PF, RR, Sp
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.
Otago: 2025 | Regionally Not Threatened
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 “Conservation Status of Indigenous Vascular Plants in Otago, 2025” Jarvie S 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
Webb, C.J.; Simpson, M.J.A. 2011: Seeds of New Zealand Gymnosperms and Dicotyledons. Christchurch, Manuka Press.
Attribution
Fact Sheet Prepared for NZPCN by: P.J. de Lange (30 August 2011) description adapted from Raven & Raven (1976) and Webb & Simpson (2001).