The New Zealand Plant Conservation Network

Species

Epilobium hirtigerum

Etymology

Epilobium: From the Greek epi- 'upon' and lobos 'a pod', the flowers appearing to be growing on the seed pod.

Common Name(s)

Hairy willowherb

Current Conservation Status

2018 - At Risk - Recovering

Conservation status of New Zealand indigenous vascular plants, 2012
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2012 using the New Zealand Threat Classification System (NZTCS). This report includes a statistical summary and brief notes on changes since 2009 and replaces all previous NZTCS lists for vascular plants. Authors: Peter J. de Lange, Jeremy R. Rolfe, Paul D. Champion, Shannel P. Courtney, Peter B. Heenan, John W. Barkla, Ewen K. Cameron, David A. Norton and Rodney A. Hitchmough. File size: 792KB

Previous Conservation Status

2012 - Threatened - Nationally Critical
2009 - Threatened - Nationally Critical
2004 - Data Deficient

Qualifiers

2012 - DP, EF, SO
2009 - DP, EF, SO

Authority

Epilobium hirtigerum A.Cunn.

Family

Onagraceae

Flora Category

Vascular - Native

NVS Species Code

EPIHIR

Structural Class

Dicotyledonous Herbs other than Composites

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.

Distribution

Indigenous. New Zealand, North, South and Chatham Islands. Also known from 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.

Features

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 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.

Flowering

September to May

Flower Colours

Red / Pink,White

Fruiting

November to 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.

Threats

Most recent (i.e. last 15 years) records 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.

Chromosome No.

2n = 36

Endemic Taxon

No

Endemic Genus

No

Endemic Family

No

Life Cycle and Dispersal

M

This page last updated on 27 May 2019