Rhododendron macrophyllum D. Don ex G. Don

vernacular Pacific rhododendron — species · Ericaceae

USDA: RHMA3
GBIF: 7894533
Rank: species

Pacific rhododendron (Rhododendron macrophyllum) — Platephotograph · Karla SalpCC BY-NC source · iNaturalist ↗

§2Habit & range

Growth habit: Shrub, Tree
Duration: Perennial
Group: Dicot
Family: Ericaceae Juss.
Genus: Rhododendron

§2a

Native status, by region

CAN Canada Native
L48 Lower 48 States Native

§2b

County-level range

· 40 counties across 3 states/territories

Legend Native · 40 Introduced · 0 Both · 0 Hover a county for detail.

§3Cultivation specs · USDA

Recorded by the USDA Plant Materials Program.

§3a

Tolerances

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

§3b

Climate & soil

Cold tolerance: 7 °F minimum
Frost-free days: 270 min.
Precipitation: 55–125 in/yr
pH range: 5.5–7
Root depth: 12 in min.
Fertility need: Medium
Soil texture: medium, fine

§3c

Form & growth

Growth form: Multiple Stem
Growth rate: Moderate
Lifespan: Moderate
Mature height: 15 ft
Height @ 20 y: 10 ft
Foliage texture: Coarse
Foliage colour: Dark Green
Porosity (summer): Dense
Porosity (winter): Dense
Flower colour: Purple
Fruit colour: Black
Fire resistant: No
N fixation: None
Toxicity: Moderate

§3d

Reproduction

Bloom period: Spring
Seed abundance: High
Seed begins: Summer
Seed ends: Fall
Spread rate: Rapid
Stratify: No
Seeds / lb: 2,500,000
Propagation: seed, cuttings, bare root, container

§3e

Use & availability

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

§4Counties, by state

Recorded in 40 counties across 3 states/territories.

California view state ↗ 9 N ▾

Oregon view state ↗ 20 N ▾

Washington view state ↗ 11 N ▾

§5Sources & provenance

USDA PLANTS

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

plants.usda.gov/RHMA3 ↗

GBIF Backbone

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

gbif.org/species/7894533 ↗

Record version

Cached and built locally. Source version on this record:

usda-plants-mt-2026-05-26

fetched 2026-05-26T16:37:38Z