Kalmia polifolia

Bog Laurel

Bog Laurel
Photo courtesy of David H. Firmage

Flora, fauna, earth, and sky...
The natural history of the northwoods

Name:

• Kalmia, after Peter Kalm, 18th Century Swedish naturalist
• polifolia, from the Greek polus (polys), many, and the Latin folium, leaf, hence "many-leaved".
• Common Name from the prefered habitat of this hardy northern laurel
• Other common names include Gold Withy, Pale Laurel, Swamp Laurel, kalmia à feuilles d'andromède (Fr)

Taxonomy:

• Kingdom Plantae, the Plants
  • Division Magnoliophyta, the Angiosperms (flowering plants)
    • Class Magnoliopsida, the Dicotyledons
    • Subclass Dilleniidae
      • Order Ericales
        • Family Ericaceae, the Heaths, with Bog Rosemary (Andromeda polifolia var. glaucophylla), Bearberry (Arctostaphyllos uva-ursi), Leatherleaf (Chamaedaphne calyculata), Labrador Teas (Ledum spp.), and the blueberries, bilberries, and cranberries (Vaccinium spp.).
          • Genus Kalmia, the Laurels
• Taxonomic Serial Number: 23679
• Also known as Chamaedaphne glauca, Kalmia polifolia var. rosmarinifolia

Description:

• A small shrub of bogs with opposite leaves and bell-shaped flowers.
• Leaves opposite, elliptic, crowded toward stem apex, divergent from stem, simple. Leaves without stems; surface yellowish green, 1.2-2.8 cm long, 0.1-0.9 cm wide, margin entire, apex acute or obtuse.
• Stem erect, round, "regular".
  • Twigs reddish violet, not odoriferous, elliptic, 1 mm in diameter, smooth, glabrous, without glands. Pith yellowish orange, round, continuous; Sap translucent.
  • Bark reddish violet or gray. Branches ascending, reddish violet or gray, round.
• Flowers serotinous, formed on long shoots, with sepals and petals readily distinguishable from one another. Perfect or female flowers red, 6-9 flowers per inflorescence, perianth of two whorls. Petals or petal lobes 5, "normal", shallowly triangular.
• Fruit a capsule, violet-red.
• Seed many, yellow, irregularly oblong, 1.5 mm long, 0.3 mm wide.

Identification:

Distribution:

Habitat:

• Shade; growth most vigorous in partial shade.
• Moist, well drained sites prefered
• Bog mats and pine swamps. pH 4.5-5.
• Cool, acidic soil (pH 3.0 to 7.9)

Fire:

Associates:

• Trees: Tamarack (Larix laricina), Black Spruce (Picea mariana)
• Shrubs: Bog Rosemary (Andromeda polifolia var. glaucophylla), Bog Birch (Betula pumila), Leatherleaf (Chamaedaphne calyculata), Large Cranberry (Vaccinium macrocarpon), Small Cranberry (Vaccinium oxycoccus)
• Herbs: Wild Calla or Water Arum (Calla palustris), Wool Fruited Sedge (Carex lasiocarpa), Round Leaf Sundew (Drosera rotundifolia), Cotton Grass (Eriophorum spp.),Purple Pitcher Plant (Sarracenia purpurea)
• Ground Covers: Sphagnum Moss (Sphagnum spp.)

History:

Uses:

• All parts of the plant are poisonous including the nectar, which can result in poisonous honey. Andromedotoxins (grayanotoxins) are resins derived from diterpenes. Several have been found in many members of the Heath family and are toxic if sufficient vegetation is eaten.

Reproduction:

• Reproduces by seed and vegetatively by rhizomes
• Flowers are visited most commonly by Andrena vivina, Apis melifera, Bombus affinis, Bombus bimaculatus, Bombus borealis, Bombus fervida, Bombus griseocollis, Bombusimpatiens, Bombusternarius, Bombus terricola, Bombus vagans,Colletes inaegualis
• Seed probably wind-dispersed.

Propagation:

• By seed
• Germination does not require stratification; does require light. Optimal temperature for initial growth 70°-75°F.

Cultivation:

• Hardy to USDA Zone 3 (average minimum annual temperature -40ºF)

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