Epilobium glaberrimum Barbey

vernacular glaucus willowherb — species · Onagraceae

USDA: EPGL
GBIF: 3189150
Rank: species

glaucus willowherb (Epilobium glaberrimum) — Platephotograph · Courtney Matzke source · iNaturalist ↗

§2Habit & range

Growth habit: Forb/herb
Duration: Perennial
Group: Dicot
Family: Onagraceae Juss.
Genus: Epilobium

§2a

Native status, by region

CAN Canada Native
L48 Lower 48 States Native

§2b

County-level range

· 2 counties across 1 state

Legend Native · 2 Introduced · 0 Both · 0 Hover a county for detail.

§3Cultivation specs · USDA

Recorded by the USDA Plant Materials Program.

§3a

Tolerances

Drought: Low
Shade: Low
Moisture use: Medium
Fire: High
Salinity: None
Anaerobic: None
CaCO₃: Medium
Hedging: None

§3b

Climate & soil

Cold tolerance: -8 °F minimum
Frost-free days: 200 min.
Precipitation: 12–20 in/yr
pH range: 6.1–7.5
Root depth: 8 in min.
Fertility need: Low
Soil texture: medium, fine

§3c

Form & growth

Growth form: Rhizomatous
Growth rate: Slow
Lifespan: Moderate
Mature height: 2 ft
Foliage texture: Medium
Foliage colour: Dark Green
Porosity (summer): Porous
Porosity (winter): Porous
Flower colour: Purple
Fruit colour: White
Fire resistant: No
N fixation: None
Toxicity: None

§3d

Reproduction

Bloom period: Mid Summer
Seed abundance: High
Seed begins: Summer
Seed ends: Summer
Spread rate: Moderate
Stratify: No
Seeds / lb: 3,000,000
Propagation: seed

§3e

Use & availability

Commercial availability: No Known Source
Nursery stock: No
Browse palatability: Low
Graze palatability: High
Palatable, human: Yes
Protein potential: Low
Lumber: No
Christmas tree: No

§4Counties, by state

Recorded in 2 counties across 1 state.

Montana view state ↗ 2 N ▾

§5Sources & provenance

USDA PLANTS

Symbol, taxonomy, distribution, cultivation specs, native status. Public domain.

plants.usda.gov/EPGL ↗

GBIF Backbone

Canonical taxonomic identity, synonym resolution, cross-refs. CC0.

gbif.org/species/3189150 ↗

Record version

Cached and built locally. Source version on this record:

usda-plants-mt-2026-05-25

fetched 2026-05-25T18:27:19Z