Clethra alnifolia L.

vernacular coastal sweetpepperbush — species · Clethraceae

USDA: CLAL3
GBIF: 2888323
Rank: species

coastal sweetpepperbush (Clethra alnifolia) — Platephotograph · Tom PotterfieldCC BY-NC-SA source · iNaturalist ↗

§2Habit & range

Growth habit: Shrub
Duration: Perennial
Group: Dicot
Family: Clethraceae Klotzsch
Genus: Clethra

§2a

Native status, by region

CAN Canada Native
L48 Lower 48 States Native

§2b

County-level range

· 5 counties across 1 state

Legend Native · 5 Introduced · 0 Both · 0 Hover a county for detail.

§3Cultivation specs · USDA

Recorded by the USDA Plant Materials Program.

§3a

Tolerances

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

§3b

Climate & soil

Cold tolerance: -23 °F minimum
Frost-free days: 150 min.
Precipitation: 35–60 in/yr
pH range: 4.5–7
Root depth: 16 in min.
Fertility need: Medium
Soil texture: coarse, medium

§3c

Form & growth

Growth form: Multiple Stem
Growth rate: Moderate
Lifespan: Moderate
Mature height: 16 ft
Height @ 20 y: 16 ft
Foliage texture: Coarse
Foliage colour: Green
Porosity (summer): Moderate
Porosity (winter): Porous
Flower colour: White
Fruit colour: Brown
Fire resistant: No
N fixation: None
Toxicity: None

§3d

Reproduction

Bloom period: Summer
Seed abundance: Low
Seed begins: Summer
Seed ends: Fall
Spread rate: Slow
Stratify: No
Propagation: seed, bare root, container

§3e

Use & availability

Commercial availability: Routinely Available
Nursery stock: No
Browse palatability: Medium
Graze palatability: Low
Palatable, human: No
Protein potential: Low
Lumber: No
Christmas tree: No

§4Counties, by state

Recorded in 5 counties across 1 state.

Rhode Island view state ↗ 5 N ▾

§5Sources & provenance

USDA PLANTS

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

plants.usda.gov/CLAL3 ↗

GBIF Backbone

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

gbif.org/species/2888323 ↗

Record version

Cached and built locally. Source version on this record:

usda-plants-mt-2026-05-25

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