Bloomipedia
Western bog laurel (Kalmia microphylla)
Photo: Tanya Riseman via iNaturalist · CC BY 4.0 · resized

Flower profile

Western bog laurel

Kalmia microphylla

Western bog laurel (Kalmia microphylla) is a shrub in the Ericaceae family, native in the lower 48 states, blooming mostly May–July across the U.S.

Native in the lower 48

Western bog laurel is a flowering plant that USDA PLANTS lists as native in the lower 48 states. It's on our flower lists for 2 states, and across the U.S. it's most often seen in bloom in May–July.

10states where USDA records it
2Bloomipedia state lists include it
3,761U.S. sightings*

*iNaturalist research-grade observations, as of October 17, 2026.

On our lists for: Alaska, Wyoming

Quick look

Kalmia microphylla, known as alpine laurel, bog laurel, swamp-laurel, western bog-laurel or western laurel, is a species of Kalmia of the family Ericaceae. It is native to North America and can be found throughout the western US and western and central Canada below the subarctic.

  • It belongs to the Ericaceae family. iNaturalist
  • USDA PLANTS describes it as a shrub / a subshrub with a perennial life cycle. USDA PLANTS
  • USDA PLANTS lists it as native in the lower 48 states and records it in 10 states. USDA PLANTS
  • NatureServe lists it as native to Alaska and Wyoming. NatureServe
  • In Alaska, most iNaturalist sightings of it in flower come in May–June. iNaturalist
  • In Wyoming, most iNaturalist sightings of it in flower come in June–July. iNaturalist
  • USDA PLANTS lists its flower color as purple. USDA PLANTS
  • USDA PLANTS gives its bloom period as late spring. USDA PLANTS
  • USDA PLANTS lists a mature height of about 1 ft. USDA PLANTS
  • iNaturalist has 456 research-grade sightings of it in Alaska, ranking #94 among the 121 flowers on our Alaska list. iNaturalist
  • iNaturalist has 279 research-grade sightings of it in Wyoming, ranking #100 among the 113 flowers on our Wyoming list. iNaturalist

When does it bloom?

Flowering records by month across the U.S. (iNaturalist research-grade observations marked “Flowering”) (762 records)
Bloom time in the 2 states whose Bloomipedia list includes it
StateTypePeak bloomSightings*
AlaskaNativeMay–June456
WyomingNativeJune–July279

Conservation status

Federal (U.S. ESA)
Not listed No U.S. Endangered Species Act listing in the USFWS ECOS database. USFWS ECOS
NatureServe global
G5 Secure worldwide. NatureServe
Alaska
No list Alaska has no state law listing endangered or threatened plants, so we show NatureServe's Alaska ranks instead. NatureServe: SNR, not yet ranked in Alaska.
Wyoming
No list Wyoming has no state law listing endangered or threatened plants, so we show NatureServe's Wyoming ranks instead. NatureServe: S4, apparently secure in Wyoming.
Rare elsewhere
Other states where NatureServe ranks it rare or missing: NV (S2). (S1 critically imperiled, S2 imperiled, SH possibly extirpated, SX presumed extirpated.)

Checked October 17, 2026. Rankings and lists can change, so follow the links for the latest.

Can you eat it?

For peopleNot well documented

None of the sources we checked (NC State Extension (no page for this plant), USDA PLANTS) say whether it's edible or poisonous for people.

For petsNot well documented

It isn't on the ASPCA plant list. For context only: ASPCA lists a related species, Kalmia augustifolia (“Lambkill”), as toxic to dogs and cats. That doesn't tell us about this species, so keep pets away to be safe. ASPCA

🌿 Never eat a wild plant unless you're certain of its ID; this isn't medical advice. Worried about a person? Call Poison Control at 1-800-222-1222. Worried about a pet? Call your vet.

Where does it grow?

USDA PLANTS records Western bog laurel in 10 states.

recorded by USDA PLANTS on our state lists not recorded

See the full list of states

Alaska, California, Colorado, Idaho, Montana, Nevada, Oregon, Utah, Washington, Wyoming.

Alaska counties with USDA records: Haines, Juneau, Ketchikan Gateway, Sitka, Yakutat.

Wyoming counties with USDA records: Albany, Big Horn, Carbon, Fremont, Johnson, Park, Sheridan, Sublette, Teton.

Growing conditions

USDA PLANTS gives Western bog laurel a low shade tolerance, low drought tolerance and medium moisture use. It is rated for soil pH 6.0 to 7.3 and winter lows down to -28 °F.

Shade tolerance
Low
Drought tolerance
Low
Moisture use
Medium
Soil textures it is adapted to
coarse, medium
Soil pH range
6.0 to 7.3
Minimum temperature tolerated
-28 °F
Frost-free days needed (minimum)
85
Annual precipitation range
12 to 20 inches
Minimum root depth
12 inches
Salinity tolerance
None
Fertility requirement
Low
Growth rate
Slow
Lifespan
Long
Active growth period
Spring and Summer
Fruit or seed
Brown · Summer to Summer
Can be propagated by
bare root, container, cuttings, seed
Commercial availability
Contracting Only

From the USDA PLANTS characteristics data for KAMI. USDA ratings are general guidance for the species, not a guarantee for your garden.

Names, range and relatives

Native status by region (USDA PLANTS): Alaska: Native; Canada: Native; Lower 48 states: Native.

Other scientific names (synonyms in USDA PLANTS): Kalmia occidentalis.

County records: USDA PLANTS lists it in 101 counties across 9 states; the most are in Washington (21), Oregon (20), California (17).

Other Kalmia on Bloomipedia (3): Mountain laurel, Sheep laurel, Alpine azalea.

More from the Ericaceae family (55 on Bloomipedia; most observed first): Ghost pipe, Rhododendrons and azaleas, Striped wintergreen, Eastern teaberry (wintergreen), Salal, Woodland pinedrops, Pinesap, Trailing arbutus (mayflower).

More Alaska flowers

Lingonberry (Vaccinium vitis-idaea)

Lingonberry

Vaccinium vitis-idaea

Native

🌼 Few flowering records in AK
Black crowberry (Empetrum nigrum)

Black crowberry

Empetrum nigrum

Native

🌼 Few flowering records in AK
Bog bilberry (Vaccinium uliginosum)

Bog bilberry

Vaccinium uliginosum

Native

🌼 Blooms in AK: May–July

Sources