bog birch

(Betula pumila)

Conservation Status

 

No image available

 
 
  IUCN Red List

LC - Least Concern

     
  NatureServe

N5 - Secure

SNR - Unranked

     
  Minnesota

not listed

     
           
Wetland Indicator Status
     
  Great Plains

OBL - Obligate wetland

     
  Midwest

OBL - Obligate wetland

     
  Northcentral & Northeast

OBL - Obligate wetland

     
           
 
Description
 
 

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.

 
     
 

Height

 
 

3 to 13 (1 to 4 m)

 
     
 

Flower Color

 
 

Female catkins green and reddish

 
     
 

Similar Species

 
     
     
 
Habitat
 
 

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

 
     
 
Biology
 
 

Flowering

 
 

Late mid-April to mid-May

 
     
 

Pests and Diseases

 
 

 

 
     
 
Use
 
 

 

 
     
 
Distribution
 
 

Distribution Map

 

Sources

2, 3, 4, 5, 7, 8, 24, 28, 29, 30,

 
  12/2/2021      
         
 

Nativity

 
 

Native

 
         
 

Occurrence

 
 

Common in Minnesota

 
         
 
Taxonomy
 
  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  
 

Order

Fagales (beeches, oaks, walnuts, and allies)  
 

Family

Betulaceae (birch)  
  Subfamily Betuloideae  
 

Genus

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.

 
 

bog birch (Betula pumila var. glandulifera)

swamp birch (Betula pumila var. pumila)

swamp birch (Betula pumila var. renifolia) (?)

 
       
 

Synonyms

 
 

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

 

 

 

 

 

 

 

 

 

 

Glossary

Catkin

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

 

Elliptic

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

 

Lenticel

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

 

Node

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

 

Pedicel

On plants: the stalk of a single flower in a cluster of flowers. On Hymenoptera and Araneae: the narrow stalk connecting the thorax to the abdomen.

 

Petiole

The stalk of a leaf blade or compound leaf that attaches the leaf blade to the stem.

On plants: The stalk of a leaf blade or compound leaf that attaches the leaf blade to the stem. On ants and wasps: The basal stalk of the abdomen.

 

Spur

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 occurs only at the shrubby edges of sphagnum bogs.

 

Hybrids

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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    bog birch   bog birch  
           
 
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Betula pumila
The Tree Library
  Betula pumila  
 
About

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
 
   
 
About

Aug 31, 2021

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

 

 

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  Luciearl
Sept. 2021

Location: Fairview Twp, Cass County

bog birch

 
           
 
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Created: 12/2/2021

Last Updated:

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