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Kalmia carolina Small
Carolina Bog Myrtle
Federal Protection: No US federal protection
State Protection: Threatened
Global Rank: G4
State Rank: S1
Element Locations Tracked in Biotics: Yes
SWAP 2015 Species of Greatest Conservation Need (SGCN): Yes
SWAP 2025 Species of Greatest Conservation Need (SGCN): Yes
2025 SGCN Priority Tier: High Conservation Concern
Element Occurrences (EOs) in Georgia: 8
Habitat Summary for element in Georgia: Open swamps and wet meadows; mountain bogs and Atlantic white-cedar swamps
Erect, evergreen shrub 1 - 6.5 feet (0.3 - 2 meters) tall, with nearly hairless but sticky twigs, forming colonies. Leaves are 0.6 - 3 inches long and 0.2 - 1 inch wide (1.5 - 8 cm long and 0.5 - 2.5 cm wide), usually in whorls of three (rarely opposite), oval; the upper leaf surface is deep blue-green and hairless; the lower surface is pale green and covered with minute glandular hairs. Flower clusters are held in the angles between the stem and last year’s leaves. Flowers are about 0.2 inch (0.5 cm) wide, white, pink, or rose, bowl-shaped with 5 shallow lobes and a ring of dark pink dots near the throat; the tips of the stamens are tucked into 10 tiny pockets around the inside of the “bowl.” Sepals are finely hairy and lacking glands. A pair of small leafy bracts, with few or no glands, lies between the flower and the nearest set of leaves. Fruit is a round, 5-lobed capsule, about 0.1 inch (0.25 - 0.35 cm) wide.
Mountain Laurel (Kalmia latifolia) has glossy, dark green leaves up to 4.7 inches (12 cm) long and 2 inches (5 cm) wide, reddish, shredding bark, and sticky, white flowers up to 1 inch wide held in clusters at the tips of twigs.
Wicky (Kalmia hirsuta) is a low shrub of the Coastal Plain, with alternate leaves, flowers scattered along the stems, and hairy twigs, leaves, and flowers.
None in Georgia.
Mountain bogs, seepage slopes and boggy streamsides in Fall Line sandhills, often with Atlantic White Cedar and Sweet Pitcherplant.
Carolina Bog Laurel flowers have an unusual pollination mechanism in common with other members of this genus: the pollen-bearing tips (anthers) of the stamens are tucked into 10 tiny pockets on the inner surface of the flower; the stamens are under tension, and, once the pollen is ripe, the weight of a visiting insect – usually a bee – triggers the stamen. The anther pops out of the pocket and dusts the bee with pollen. The pollen is then carried to the flowers of other Carolina Bog Laurel plants where cross-pollination occurs (Carolina Bog Laurel will also set fruit as a result of self-pollination). Its abundant seeds are minute but winged, and are dispersed by gravity and wind.
Surveys are best conducted during flowering (April–May) but the whorled, blue-green leaves are distinctive all year.
Georgia, South Carolina, North Carolina, and Virginia. In Virginia, this species’ range overlaps with a related northern species, Sheep-kill (Kalmia angustifolia). Some authors treat Kalmia carolina as a variety of Kalmia angustifolia.
Conversion of bog habitat to pasture and farmland; invasion of habitat by competing shrubs and trees in the absence of fire; draining and ditching of wetlands. Changes in hydrology due to altered temperature and rainfall patterns related to climate change.
Kalmia carolina is ranked S1 by the Georgia Department of Natural Resources, indicating that it is critically imperiled in the state. Eight populations have been documented in Georgia. Almost half occur in mountain bogs in one county in the Chattahoochee National Forest, and half occur in one county on private property in the Fall Line sandhills.
Protect habitats from draining, ditching, and other hydrologic disturbances. Protect habitats from logging and conversion to other land uses. Use hand-clearing to reduce competition and create gaps in the canopy or allow prescribed fires in adjacent uplands to burn into bogs and seeps.
Chafin, L.G. 2007. Field guide to the rare plants of Georgia. State Botanical Garden of Georgia and University of Georgia Press, Athens.
Foote, L.E. and S.B. Jones, Jr. 1989. Native shrubs and woody vines of the southeast. Timber Press, Portland, Oregon.
GADNR. 2020. Element occurrence records for Kalmia carolina. Georgia Department of Natural Resources, Wildlife Resources Division, Social Circle, Georgia.
Godfrey, R.K. 1988. Trees, shrubs, and woody vines of northern Florida and adjacent Georgia and Alabama. University of Georgia Press, Athens.
Lance, R. 2004. Woody plants of the southeastern United States: a winter guide. University of Georgia Press, Athens.
Liu, S., K.E. Denford, J.E. Ebinger, J.G. Packer, G.C. Tucker. 2009. Species account for Kalmia angustifolia var. carolina. Flora of North America, Vol. 8. http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=250065667
Lovell, J. H. and H.B. Lovell. 1934. The pollination of Kalmia angustifolia. Rhodora 36(422): 25-28. https://www.jstor.org/stable/23300536
NatureServe. 2019. Kalmia carolina comprehensive report. NatureServe Explorer. Arlington, Virginia. http://explorer.natureserve.org/servlet/NatureServe?searchName=Kalmia+carolina
Radford, A.E., H.E. Ahles, and C.R. Bell. 1968. Manual of the vascular flora of the Carolinas. University of North Carolina Press, Chapel Hill.
Rathcke, B. 1988. Interactions for pollination among co-flowering shrubs. Ecology 69: 446-57. https://esajournals.onlinelibrary.wiley.com/doi/abs/10.2307/1940443
Rathcke, B. 1988. Flowering phenologies in a shrub community: competition and constraints. Journal of Ecology 76(4): 975-994. https://www.jstor.org/stable/2260627
Small, J.K. 1933. Manual of the southeastern flora. 1972 Reprint Edition. Hafner Publishing Company, New York.
Weakley, A.S. 2015. Flora of the southern and mid-Atlantic States. University of North Carolina Herbarium, University of North Carolina, Chapel Hill. http://www.herbarium.unc.edu/flora.htm
Linda G. Chafin
L. Chafin, Apr. 2007: original account
K. Owers, Feb. 2010: added pictures
L. Chafin, March 2020: updated original account.
