This fine-textured, deciduous shrub forms dense colonies and prefers sunny, moist to wet conditions. It’s intolerant of shade and is often found in open bogs, fens, swamps, and lake shores, where it adapts to sandy soils. It has a multi-branched, irregular form with brown to deep-red branches and rounded, coarsely toothed leaves that turn yellow in fall. Like others in the Betulaceae family, bog birch reproduces by samaras (fruits with papery wings) that travel by wind, water, or gravity. It also propogates by rhizomes and branch layering. This species frequently hybridizes. Although normally in the 6- to 8-foot range, it may grow 12’ tall with a similar spread, which makes it useful in wetland restoration projects. It has high wildlife value, supporting over 400 species of caterpillars.
Betula pumila var. glandulifera is native to the northern states and to most of Canada. It’s threatened in Ohio and threatened to rare in other areas because of its vulnerability to invasive species when the hydrology (water movement) of its habitat is altered. Overshadowing by other species and the influence of climate change are also affecting its rate of survival.
Betula is the Latin word for birch tree. The species name, pumila, means “dwarf,” referring to the small size of this species. Glandulifera comes from the Latin words glandula (gland) and ferre (to bear). Two varieties are sometimes listed as var. pumila and var. glandulifera; the amount of glands and hair on the leaves is the determining factor. Flora of North America, a comprehensive taxonomic guide to our continent north of Mexico, treats these differences as normal variations within the species and does not accept these varieties.
Aside from its requirement for consistent moisture, especially during the first year, bog birch is a low-maintenance plant. Minimal pruning is required, although dead or damaged branches may be removed in early spring to encourage new growth.
Native habitats include open bogs, fens, peatlands, swamps, lake shores, and low areas of sand dunes with adequate moisture. Suggested companion plants include black chokeberry, silky dogwood, common ninebark, and American hornbeam. Bog birch is an attractive addition to rain gardens and wetter areas of the landscape.
Plant Characteristics:
Most often grows 6-8’ tall, but can range between 4-12' tall. Spreads to form colonies.
Prefers full sun; needs 6+ hours for best growth.
Prefers moist to wet soils. Adapts to shallow, gravelly loams; heavy clays; sandy soils; and poor, wet, boggy soils.
Reddish male catkins develop on 1-year-old twigs in fall as a spike of tightly appressed scales that open in spring. Erect, cylindrical, yellow female catkins grow on new, spur-like lateral branches on the same branch as male catkins. Fruits are clusters of winged nutlets ¼” long, green maturing to brown.
Alternate, simple, ovate-shaped leaves appear mostly in pairs (sometimes in threes) on twigs and singly on new branches. Margins are coarsely serrated. Tip is broadly rounded and base is tapered to a short stalk. Upper surface is smooth, dark green, and often dotted with glands; lower surface is lighter green.
Multiple stems grow profusely from the base. Twigs are brown to deep maroon with scattered lenticels; new growth is hairy, becoming smooth in second year. Older bark is gray to reddish brown with pale lenticels.
Reproductive System: Male and female flowers are borne separately on same plant (monoecious) but are not self-fertile. Also reproduces by rhizomes.
Wildlife Value:
Host plant to 403 species of Lepidoptera larvae, including zigzag fircula, green comma, and lettered habrosyne moths. Seeds are eaten by sharp-tailed grouses and by songbirds such as chickadees, juncos, and finches. Deer browse the foliage.
Medicinal, Edible, and Other Uses:
The Ojibwa used B. pumila medicinally as a gynecological aid and as a respiratory aid.
Leaves are edible, according to botanist/forager Laura Reeves of Prairie Shore Botanicals.
Colorful first-year stems are used to weave baskets.
Resources:
Minnesota Wildflowers: https://www.minnesotawildflowers.info/shrub/bog-birch#:~:text=The%20two%20more%20widely%20accepted,has%20hairier%20leaves%20without%20glands.
E-Flora BC: https://linnet.geog.ubc.ca/Atlas/Atlas.aspx?sciname=Betula%20pumila%20var.%20glandulifera
NW Wildflowers: https://nwwildflowers.com/compare/?t=Betula+pumila,+Betula+glandulosa
Toadshade Wildflower Farm: https://www.toadshade.com/Betula-pumila.html
Gardenia: https://www.gardenia.net/plant/betula-pumila-bog-birch
The Friends of the Wildflower Garden: https://www.friendsofeloisebutler.org/pages/plants/birch_bog.html
Prairie Shore Botanicals: https://shorturl.at/EH8lq
Photo credit: Mary Krieger