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

Rhododendron macrophyllum D. Don ex G. Don
Pacific rhododendron (California rhododendron)
Ericaceae (Crowberry family)

Introduction to Vascular Plants

© Brian Klinkenberg  Email the photographer   (Photo ID #14215)

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Distribution of Rhododendron macrophyllum
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Introduction

Our native rhododendron has broadly campanulate, pink to rosy purple, occasionally white, flowers spotted yellow. The truss holds 10-20 flowers. The leaves are oblong to elliptic and up to nine inches long. Grows to five feet in 10 years. Blooms in mid to late spring.

Note Author: Gary Lewis, Phoenix Perennials

Species Information

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General:
Erect to spreading shrub; stems branched, 1-8 m tall, glabrous but finely hairy when young.
Leaves:
Evergreen, leathery, oblong-elliptic, 8-20 cm long, entire, glabrous or nearly so, dark green above, paler beneath; stalks 1-2 cm long.
Flowers:
Many, in terminal clusters; flower stalks glabrous, up to 5 cm long; corollas pale pink to deep rose-purplish, spotted red-brown, tubular bell-shaped, 2.5-4 cm long, up to 5 cm across, deeply 5-lobed, lobes spreading and edges wavy; calyces minute, very shallowly lobed; stamens 10, filaments sparsely short-hairy on the lower half; anthers oblong, red-brown, 2-3 mm long.
Fruits:
Capsules, 1.5-2 cm long, rusty-hairy and glandular, woody.

Source: The Illustrated Flora of British Columbia

USDA Species Characteristics

Flower Colour:
Purple
Blooming Period:
Spring
Fruit/Seed characteristics:
Colour: Black
Present from Summer to Fall
Source:  The USDA

Habitat / Range

Mesic to moist forests in the lowland and montane zones; locally frequent in the Cascade Mountains, rare on S Vancouver Island; S to MT and N CA.

Source: The Illustrated Flora of British Columbia

Ecology

Ecological Framework for Rhododendron macrophyllum

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

Minimum

Average

Maximum

Elevation (metres) 490 607 1330
Slope Gradient (%) 0 9 72
Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]
9 2 330
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
2 3 6
Modal Nutrient Regime
Class
B
Number of field plots
 species was recorded in:
61
Modal BEC Zone Class
IDF
All BEC Zones (# of stations/zone) species was recorded in: CWH(23), ESSF(3), IDF(35)

Climate

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 cool mesothermal.

Synonyms and Alternate Names

Rhododendron californicum Hook.

Taxonomic and Nomenclatural Links

Additional Photo Sources

General References