Epilobium hirtigerum
Common names
hairy willowherb
Biostatus
Native
Category
Vascular
Structural class
Herbs - Dicotyledons other than Composites
Flower colours
Red/Pink, White
Detailed description
Robust perennial, stoloniferous, dull grey to grey-green, reddish tinged herb, 0.2–1.8 m tall. Plants distinctly hairy, all parts except petals densely covered in long spreading, and short erect, eglandular, greyish hairs; hairs of inflorescence glandular. Stems usually unbranched; woody near base. Stolons numerous (especially in winter), arising from base of stems, and sometimes from rootstock, dark red, glabrescent. Stolon leaves bright green, streaked, tinged or blotched dark red, glabrous, 50–80 × 10–40 mm, broadly ovate,to elliptic, base oblique to broadly cuneate, sometimes attenuate, apex acute to obtuse, sometimes rounded, margins coarsely and ± evenly serrated, teeth up to 18 on each side; lateral veins 2–4 each side of midrib, conspicuous. Leaves of stems and inflorescences alternate except near base where opposite, glaucous, hairy; 15–60 × 2–8 mm, linear to narrowly lanceolate, base acute or acuminate, apex acuminate, margins coarsely serrate, sometimes undulate, teeth 0–12 on each side, evenly distributed or concentrated toward leaf apex; lateral veins 2–4 each side of midrib, usually inconspicuous. Inflorescence erect. Flowers erect, up 16 mm diameter. Pedicel 0–70 mm long. Ovaries 14–30 mm long, invested with spreading, appressed, glandular hairs. Sepals keeled, 2.5–5.3 × 0.8–1.0 mm, invested with spreading, appressed, glandular hairs. Floral tube 0.5–0.9 mm deep. 1.0–1.5 mm diameter at apex, internally bearing a conspicuous ring of long white hairs. Petals white (North Island and South Island) or rose-pink (South Island), 2.8–8.0 × 1.8–5.2 mm wide, notched, notch 0.6–1.8 mm deep, petals of white-flowered plants often shorter than sepals, scarcely spreading apart at anthesis, petals of rose-pink –flowered plants longer than sepals, spreading widely at anthesis. Stamens 8, of two lengths, 4 longer (0.8–4.0 mm) and 4 shorter (0.3–0.5 mm); anthers 0.5–1.2 × 0.3–0.5 mm, cream. Stigma rarely positioned above lower set of stamens; style 1.2–4.2 mm long, white, basally invested in long hairs; stigma clavate, 0.6–2.4 × 0.6–0.9 mm. Capsules on pedicels 6–15 mm long; narrowly cylindric, 35–60 mm long, densely pubescent with both long, spreading, appressed, eglandular, and shorter, erect, glandular hairs. Seeds 0.9–1.1 × 0.5 mm, orange-brown, obovoid, papillose; coma easily detached, 5–8 mm long, white.
Similar taxa
Hairy willow herb is most often confused with Epilobium cinereum which is commonly found growing in the same habitats. Epilobium cinereum differs from hairy willow herb by its smaller, spreading rather than erect growth habit, non-dimorphic, smaller (up to 40 × 7 mm), coarsely toothed leaves, larger (up to 20 mm wide), consistently dark rose-purple flowers than open widely, and slightly smaller (0.8–1 mm) seeds.
Distribution
Indigenous. New Zealand: North Island, South Island, Chatham Islands. Also Australia, Indonesia and South America.
Habitat
Coastal, lowland to montane. A short-lived species of open ground, seepages on cliff faces, sparsely-vegetated wetland margins, braided riverbeds, lake edges, and swamps. Now most common in urban areas and associated wasteland.
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: EF, SO
Threats
Most records since the 1990s are from urban situations, country roadsides, within coastal areas or under willow (Salix spp.) along river banks. Plants are usually in wasteland, often within new housing developments, bordering drains, within old quarry pits or growing in cliff seepages. A common habitat is car parks, traffic islands and roadside gutters. In these sites some quite large populations have been destroyed by housing, road works and through competition from large, faster growing weeds. However, overall it now seems clear that this species is increasing its range rather than in decline.
Detailed taxonomy
Family
Synonyms
Epilobium junceum G.Forst. var. hirtigerum (A.Cunn.)Curtis, E. junceum sensu Hook.f. pro parte, E. tetragonum L. E. brasiliense Hausskn., E. sarmentaceum sensu Back. et Bakh., E. cinereum sensu Raven prop parte.
Endemic taxon
No
Endemic genus
No
Endemic family
No
Ecology
Flowering
September–May
Fruiting
November–June
Propagation technique
Easily grown from seed and rooted pieces of stem. Prefers full sun and does best in damp ground. Despite its scarcity in the wild, in cultivation this species can quickly become invasive.
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]
FAC: Facultative
Commonly occurs as either a hydrophyte or non-hydrophyte (non-wetlands).
Other information
Extra information
Most New Zealand plants have white flowers, with only a few instances of rose-purple coloured flowers (the more usual colour form in Australia) are known.
Etymology
epilobium: From the Greek epi- ‘upon’ and lobos ‘a pod’, the flowers appearing to be growing on the seed pod.
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.
EPIHIR
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 | At Risk – Recovering | Qualifiers: EF, SO
2012 | Threatened – Nationally Critical | Qualifiers: DP, EF, SO
2009 | Threatened – Nationally Critical | Qualifiers: DP, EF, SO
2004 | Data Deficient
Referencing and citations
References and further reading
Raven PH, Raven TE. 1976. The genus Epilobium in Australasia. New Zealand DSIR Bulletin 216. Government Printer, Wellington, NZ. 321 p.
Webb CJ, Simpson MJA. 2001. Seeds of New Zealand Gymnosperms and Dicotyledons. Manuka Press, Christchurch. 428 p.
Attribution
Fact sheet first prepared for NZPCN by P.J. de Lange 6 January 2008. Description adapted from Raven & Raven (1976) and Webb & Simpson (2001).
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Epilobium hirtigerum Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/epilobium-hirtigerum/ (Date website was queried)