Kalmia microphylla
Highly variable western North American shrub with two distinct varieties—var. microphylla in alpine meadows from California to Alaska and var. occidentalis in coastal belts below 900 m—with pink to rose-purple flowers.
Common Names
Bog Laurel, Alpine Laurel, Western Bog Laurel, Western Laurel, Swamp Laurel, Alpine Bog Laurel
Summary
Bog laurel is an evergreen shrub native to western North America from Alaska to central Colorado and southern California, typically 0.05–0.8 m tall, with opposite, leathery dark green leaves and a compact form. Pink or purple, bowl-shaped flowers with five fused petals form a cup and appear in clusters, blooming in spring to early summer.
It grows in boggy wetlands and moist meadows, preferring consistently moist, acidic soils and full sun to partial shade, with USDA hardiness zones 3a–9b. Propagation is possible from seed sown in spring or semi-hardwood cuttings taken in late summer or fall, and layering is also used; in cultivation it serves as a foundation or specimen plant, hedge or border accent, and can be grown in containers with winter indoor care, while avoiding overwatering to prevent root rot.
Lifecycle
Perennial
Height
0-10 feet
Spread
2-6 feet
Hardiness Zones
Zones 3a-9b
Sunlight Requirements
Ideally full sun; tolerates partial sun to partial shade
Soil Type
Moist, acidic, well-drained soil
Soil Drainage
Well-drained soil
Soil pH
6–7.5, slightly acidic to neutral, intolerant of alkaline conditions.
Bloom Color
Pink to purple
Bloom Time
Spring to Summer
Foliage Color
Dark green, shiny above and light green below.
Fall Foliage Color
No fall foliage color
Leaf Lifecycle
Evergreen broadleaf
Growth Rate
Slow
Seasons of Interest
Spring and Summer
Propagation Methods
Seeds (smoke-treated germination) in fall, Cuttings (semi-hardwood under mist) in summer, Layering
Attracts Wildlife
Attracts bees
Taxonomy
- Taxonomic Rank
- Species
- Author
- (Hook.) A.Heller
- Publication
- Bull. Torrey Bot. Club 25: 581 (1898)
Superior Taxa
- Kingdom
- Plantae
- Subkingdom
- Pteridobiotina
- Phylum
- Angiosperms
- Order
- Ericales
- Family
- Ericaceae
- Subfamily
- Ericoideae
- Genus
- Kalmia
Inferior Taxa
Kalmia microphylla var. occidentalis
Synonyms
Kalmia polifolia var. microphylla Kalmia polifolia subsp. microphylla Kalmia glauca var. microphylla