bog birch

(Betula pumila)

Conservation Status


No image available

  IUCN Red List

LC - Least Concern


N5 - Secure

SNR - Unranked


not listed

Wetland Indicator Status
  Great Plains

OBL - Obligate wetland


OBL - Obligate wetland

  Northcentral & Northeast

OBL - Obligate wetland


Bog birch is common deciduous shrub. It is native across the northern half of North America. In the United States it occurs from Maine to Maryland west to Washington and northern California. It is common in Canada, Michigan, Wisconsin, and Minnesota., but in the U.S. it is uncommon wherever else it occurs. In Minnesota it is absent in the southwest, common elsewhere. It is found in wetlands, including calcareous fens, wooded swamps, and muskegs, and on stream sides and lake shores, and at the shrubby edges of sphagnum bogs. It grows under full or partial sun in moist or wet peaty soil or calcareous sand.

Bog birch is an erect, perennial shrub that rises on multiple stems from a shallow woody root system. It can be 3 to 13 (1 to 4 m) tall and 1¼ (3 cm) in diameter at the base, but it is usually no more than 6 in height.

The stems are erect or curve upward at the base (ascending). The bark on young stems and branches is thin, smooth, dark reddish-brown, and shiny, with scattered, small, pale, inconspicuous, horizontal, corky areas (lenticels). As it ages the bark on the trunk and lower branches becomes gray and slightly rough but does not peel.

Twigs are slender and dark reddish-brown. They have numerous spur shoots. They do not have a wintergreen odor or taste. In the first year they are usually moderately covered with non-glandular hairs, sometimes almost hairless, but always with some hairs. They also have scattered, small, resinous glands, especially near the nodes. The presence of both hairs and glands is the feature that some botanists use to identify this as var. glandulifera. Winter buds are slender, round in cross section, and sharply pointed. They are covered with smooth overlapping scales.

The leaves are borne on two distinct kinds of shoots. Long shoots are produced at the tip of the twig. They are fast growing and have well-spaced nodes. Spur shoots emerge from the widely-spaced leaf axils along the long shoot. They are very slow growing and have very little growth between nodes.

Two types of leaves are produced: early leaves, also called preformed leaves; and late leaves, also called neoformed leaves. Preformed leaves overwinter in the bud and are fully formed or almost fully formed before bud burst in the spring. They are the first leaves to mature in the spring. They are produced on spur shoots and at the base of long shoots. Neoformed leaves are all of the subsequent leaves produced on long shoots. They are formed from new tissue growing at the tip of the shoot in the season that they emerge.

The leaves are alternate, 1 to 2 (25 to 50 mm) long, and to 1 (15 to 25 mm) wide. They are borne in pairs on spur shoots and singly on long shoots. Each leaf is on a 132 to ¼ (1 to 7 mm) long leaf stalk (petiole). The petiole is light green to red and may be hairy or hairless. The leaf blade is somewhat thick, egg-shaped and widest above the middle (obovate), oval and broadest in the middle (elliptic), or nearly circular. It has just 2 to 6 pairs of lateral veins. It is heart-shaped to rounded at the base and broadly angled or rounded at the tip. The upper surface is dark green and hairless. The lower surface is pale green, hairless or slightly hairy, and has scattered sunken glands. The margins have 10 or fewer coarse teeth on each side.

Male and female flowers are borne on the same plant and on the same branch. The male catkin is preformed and emerges in the late summer the year before it sheds its pollen. A single catkin is held erect or ascending at the end of a leafless branchlet formed at the tip of a current year long shoot. It is stout, erect, and 316 to (5 to 6 mm) long. It remains on the tree over the winter. When it opens the following spring it becomes brownish-yellow, spreading or pendant, and ¾ to 1¼ long.

The female catkin is also preformed but remains in the protective bud over the winter. In the spring a single catkin is held erect on a to (3 to 9 mm) long stalk (pedicel) at the end of a very short leafy branchlet. The catkin is green, stout, and short-cylindrical at first. When it flowers it becomes to 1116 (9 to 18 mm) long and reddish at the tip due to the red stigmas of the tiny flowers.

Fruits are contained in mature seed catkins. Each seed catkin is cone-like, cylinder-shaped, and 516 to ¾ long. It persists through at least part of the winter. The fruit is a tiny, two-winged nutlet (samara). The samara matures in mid-August to late September and is dispersed in the fall and early winter by wind and gravity.




3 to 13 (1 to 4 m)


Flower Color


Female catkins green and reddish


Similar Species


Moist to wet. Calcareous fens, wooded swamps, margins of sphagnum bogs, muskegs, stream sides, and lake shores,




Late mid-April to mid-May


Pests and Diseases






Distribution Map



2, 3, 4, 5, 7, 8, 28, 29, 30,








Common in Minnesota

  Kingdom Plantae (green algae and land plants)  
  Subkingdom Viridiplantae (green plants)  
  Infrakingdom Streptophyta (land plants and green algae)  
  Superdivision Embryophyta (land plants)  
  Division Tracheophyta (vascular plants)  
  Subdivision Spermatophytina (seed plants)  
  Class Magnoliopsida (flowering plants)  
  Superorder Rosanae  


Fagales (beeches, oaks, walnuts, and allies)  


Betulaceae (birch)  
  Subfamily Betuloideae  


Betula (birches)  
  Subgenus Chamaebetula (dwarf birches)  
  Section Apterocaryon  

Subordinate Taxa


Some authorities recognize four varieties of Betula pumila. Of these, only B. p. var. glandulifera is common in Minnesota. There is just a single record of B. p. var. renifolia in the state. Most taxonomists do not recognize any varieties.




Betula borealis

Betula glandulifera

Betula glandulosa var. glandulifera

Betula glandulosa var. hallii

Betula nana var. glandulifera

Betula nana var. renifolia

Betula pubescens ssp. borealis

Betula pumila var. glabra

Betula pumila var. glandulifera

Betula pumila var. pumila

Betula pumila var. renifolia


Common Names


American dwarf birch

Arctic dwarf birch

bog birch

dwarf birch

low birch

swamp birch













A slim, cylindrical, drooping cluster of many flowers. The flowers have no petals and are either male or female but not both.



Narrowly oval, broadest at the middle, narrower at both ends, with the ends being equal.



A corky, round or stripe-like, usually raised, pore-like opening in bark that allows for gas exchange.



The small swelling of the stem from which one or more leaves, branches, or buds originate.



On plants: the stalk of a single flower in a cluster of flowers. On insects: the second segment of the antennae. On Hymenoptera and Araneae: the narrow stalk connecting the thorax to the abdomen: the preferred term is petiole.



On plants: The stalk of a leaf blade or a compound leaf that attaches it to the stem. On ants and wasps: The constricted first one or two segments of the rear part of the body.



On flowers: a hollow tubular appendage, often containing nectar, formed from a sepal or petal. On branches: a short shoot bearing leaves or flowers and fruit.


What’s in a Name?

The common name of this plant suggests that it grows in bogs. However, the ground surface of bogs is acidic and low in nutrients. Bog birch is found in calcareous fens and in swamps, but only at the shrubby edges of sphagnum bogs.



Where bog birch grows in close proximity with paper birch the two species readily hybridize. These hybrids are called Sandberg’s birch (Betula × sandbergii) and have characters intermediate between the two parents.

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Betula pumila
The Tree Library
  Betula pumila  

Swamp Birch

Betula pumila (Bog Birch)
Allen Chartier
  Betula pumila (Bog Birch)  



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Other Videos
  Bog Ecology and bog birch (Betula glandulosa) pt 2 of 4
British Columbia Plant and Tree Identification

Aug 31, 2021

Filmed at Aleza Lake Research Forest near Prince George, BC on May 27, 2020.




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Created: 12/2/2021

Last Updated:

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