E-Flora BC: Electronic Atlas of the Flora of British Columbia

Epilobium leptophyllum Raf.
narrow-leaved willowherb (bog willowherb)
Onagraceae (Evening Primrose family)

Introduction to Vascular Plants

© Jamie Fenneman  Email the photographer   (Photo ID #30019)

E-Flora BC Static Map
Distribution of Epilobium leptophyllum
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Species Information

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Perennial herb, stolons thread-like and tipped with fleshy winter bulblets; stems erect,10-100 cm tall, simple to branched, usually with short leafy bundles in axils, densely short stiff-hairy.
Linear-lanceolate, 2-7.5 cm long, margins rolled under, grey short-hairy above; more or less unstalked.
Inflorescence erect, leafy, terminal; hypanthium 0.8-1.5 mm long; petals 3.5-7 mm long, white to pink; sepals 2.5-4.5 mm long, tips pointed, short stiff-hairy; anthers 0.6-0.9 mm long; ovaries 1.2-1.8 cm long, densely grey short-hairy; styles 2-3.8 mm long; stigmas narrowly club-shaped.
Capsules, 3.5-8 cm long, grey short-hairy; stalks 1-4 mm long; seeds 1.5-2.2 mm long, pimply, tuft of hairs persisting.

Source: The Illustrated Flora of British Columbia

USDA Species Characteristics

Flower Colour:
Blooming Period:
Fruit/Seed characteristics:
Colour: Brown
Present from Summer to Fall
According to the USDA, this species is a known allelopath.
Source:  The USDA

Habitat / Range

Bogs, fens, marshes and wet meadows in the montane zone; infrequent in E and N BC; N to NT, E to NF and S to NC, CO and CA.

Source: The Illustrated Flora of British Columbia


Ecological Framework for Epilobium leptophyllum

The table below shows the species-specific information calculated from
original data (BEC database) provided by the BC Ministry of Forests and Range.
(Updated August, 2013)

Site Information
Value / Class




Elevation (metres) 780 1066 1353
Slope Gradient (%) 0 0 0
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
6 6 7
Modal Nutrient Regime
Number of field plots
 species was recorded in:
Modal BEC Zone Class
All BEC Zones (# of stations/zone) species was recorded in: MS(1), SBS(1)


The climate type for this species, as reported in the: "British Columbia plant species codes and selected attributes. Version 6 Database" (Meidinger et al. 2008), is not evaluated, unknown or variable.

Synonyms and Alternate Names

Epilobium nesophilum (Fernald) Fernald
Epilobium nesophilum var. sabulonense Fernald
Epilobium palustre var. gracile (Farw.) Dorn
Epilobium palustre var. sabulonense (Fernald) B. Boivin
Epilobium rosmarinifolium Pursh
Epilobium treleaseanum Levl. p.p.

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References