Kalmia microphylla subsp. occidentalis (Hook.) A. Heller
western bog-laurel (alpine laurel; swamp laurel)
Ericaceae (Crowberry family)

Introduction to Vascular Plants


© Brian Klinkenberg     (Photo ID #274)


E-Flora BC Static Map

Distribution of Kalmia microphylla
Click here to view the full interactive map and legend

Species Information

Low shrub; stems 10-50 cm tall, much branched; young stems finely hairy but soon becoming glabrous.
Evergreen, opposite, leathery, oblong-lanceolate to narrowly oblong, (0.6) 0.8-4 cm long, (2) 3-11 mm wide, entire, margins often rolled under, shiny, dark green and glabrous above, greyish and very finely and densely short glandular-hairy beneath, often with a prominent midrib; stalks 2-5 mm long.
In terminal 1- to 12-flowered clusters; flower stalks 1-4 cm long, usually glabrous; corollas deep pinkish-rose, saucer-shaped, 1-2 cm wide; calyces deeply 5-lobed, lobes egg-shaped, 2-3 mm long, glabrous or occasionally sparsely and minutely fringed; stamens 10, held in sacs on petals until full bloom, densely hairy just above the base, otherwise glabrous.
Five-valved capsules, nearly globe-shaped, glabrous, about 4 mm wide and 5 mm long.
Two subspecies are recognized in BC:

1. Leaves oval to broadly elliptic, usually less than 2 cm long, and less than 2 times as long as wide; calyces less than 7 mm wide; plants occurring E of the Coast-Cascades Range in BC and usually at high elevations..............ssp. microphylla

1. Leaves lance-shaped, usually 2.5 cm long or longer, and 2.5-4 times as long as wide; calyces more than 7 mm wide; plants of coastal BC and intermittently inland, usuallyat low to moderate elevations..................ssp. occidentalis (Small) Taylor & MacBryde

SourceThe Illustrated Flora of British Columbia

USDA Species Characteristics

Flower Colour:
Blooming Period:
Late Spring
Fruit/Seed characteristics:
Colour: Brown
Present over the Summer
Source:  The USDA


Ecological Framework for Kalmia microphylla

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)
1040 6 2400
Slope Gradient (%)
6 0 100

Aspect (degrees)
[0 - N; 90 - E; 180 - S; 270 - W]

5 0 360
Soil Moisture Regime (SMR)
[0 - very xeric; 4 - mesic;
8 - hydric]
6 0 8
Modal Nutrient Regime
# of field plots
 species was recorded in:
Modal BEC Zone Class

All BEC Zones (# of stations/zone) species was recorded in

AT(9), BAFA(7), BWBS(4), CDF(5), CMA(2), CWH(304), ESSF(266), ICH(78), IDF(4), IMA(4), MH(60), MS(19), SBPS(2), SBS(84), SWB(3)

Habitat and Range

Peat bogs, wet peaty forests and meadows from the lowland through alpine zones; frequent throughout BC; N to AK, YT and NT, E to NW MB, and S to C CA, NV, UT, and CO.

SourceThe Illustrated Flora of British Columbia


Synonyms and Alternate Names:
Kalmia microphylla subsp. occidentalis (Small) Roy L. Taylor & MacBryde
Kalmia microphylla var. occidentalis (Small) Ebinger
Kalmia occidentalis Small
Kalmia polifolia Wangenh.
Kalmia polifolia subsp. microphylla (Hook.) Calder & Roy L. Taylor
Kalmia polifolia subsp. occidentalis (Small) Abrams
Kalmia polifolia var. microphylla (Hook.) Rehder