Your help is appreciated. We depend on donations to help keep this site free and up to date for you. Can you please help us?

Donate

Native Plant Trust: Go Botany Discover thousands of New England plants

Betula pumila — bog birch, swamp birch

Copyright: various copyright holders. To reuse an image, please click it to see who you will need to contact.

Facts

Bog birch is a native small tree that is listed as rare in the four states in which it occurs: Maine, New Hampshire, Massachusetts, and Connecticut. Its rounded leaves with coarse teeth around the margin are distinctive, and its aments (catkins) are borne upright rather than drooping. Bog birch flowers in May and June. It tends to prefer growing in calcium-rich fens, and is vulnerable to invasive species that move in when the hydrology of these habitats is altered.

Habitat

Fens, shores of rivers or lakes, swamps

New England distribution

Adapted from BONAP data

Found this plant? Take a photo and post a sighting.

North America distribution

Adapted from BONAP data

enlarge

Characteristics

Habitat
  • terrestrial
  • wetlands
New England state
  • Connecticut
  • Maine
  • Massachusetts
  • New Hampshire
Growth form
the plant is a shrub (i.e., a woody plant with several stems growing from the base)
Leaf type
the leaf blade is simple (i.e., lobed or unlobed but not separated into leaflets)
Leaves per node
there is one leaf per node along the stem
Leaf blade edges
the edge of the leaf blade has teeth
Leaf duration
the leaves drop off in winter (or they wither but persist on the plant)
armature on plant
the plant does not have spines, prickles, or thorns
Leaf blade length
25–70 mm
Leaf blade width
10–50 mm
Leaf stalk
the leaves have leaf stalks
Fruit type (general)
the fruit is dry but does not split open when ripe
Bark texture
the bark of an adult plant is thin and smooth
Twig winter color
  • brown
  • gray
  • purple
  • red
Bud scale number
there are three or more scales on the winter bud, and they overlap like shingles, with one edge covered and the other edge exposed
Show all characteristics

  • Buds or leaf scars

    Bud scale number
    there are three or more scales on the winter bud, and they overlap like shingles, with one edge covered and the other edge exposed
    Bud scar shape (Fraxinus)
    NA
    Collateral buds
    there are no collateral buds on the sides of the branches
    Leaf scar arrangement
    there is one leaf scar per node on the stem or twig
    Superposed buds
    there are no superposed buds on the branch
    Terminal bud
    there is no terminal bud on the branch
    Winter bud stalks
    the winter buds have no stalks

  • Flowers

    Carpels fused
    the carpels are fused to one another
    Enlarged sterile flowers
    there are no enlarged sterile flowers on the plant
    Flower appearance
    the flowers appear at the same time as the leaves
    Flower petal color
    NA
    Flower symmetry
    there are two or more ways to evenly divide the flower (the flower is radially symmetrical)
    Hairs on ovary (Amelanchier)
    NA
    Hypanthium present
    the flower does not have a hypanthium
    Inflorescence position
    the inflorescences grow on the twigs
    Inflorescence type
    the inflorescence is an ament (catkin; slender, usually pendulous inflorescence with crowded unisexual flowers)
    Number of pistils
    1
    Ovary position
    the ovary is below the point of petal and/or sepal attachment
    Petal and sepal arrangement
    • the flower includes only one cycle of petals or sepals
    • the flower lacks sepals and petals
    Petal appearance
    NA
    Petal fusion
    NA
    Sepal cilia (Ilex)
    NA
    Sepal tip glands
    there are no glands at the tips of the sepal lobes
    Stamen number
    1 or 2
    Stamen position relative to petals
    NA
    Stamens fused
    the stamens are not fused to one another

  • Fruits or seeds

    Berry color
    NA
    Fruit tissue origin
    there are no flower parts that form part of the fruit
    Fruit type (general)
    the fruit is dry but does not split open when ripe
    Fruit type (specific)
    the fruit is an achene (dry, usually 1-seeded, does not separate or split open at maturity)
    Nut with spines (Fagaceae)
    NA
    Wings on fruit
    the fruit has one or more wings on it

  • Glands or sap

    Sap color
    the sap is clear and watery
    Stalked glands on fruit (Rosa)
    NA

  • Growth form

    Growth form
    the plant is a shrub (i.e., a woody plant with several stems growing from the base)

  • Leaves

    Hairs on underside of leaf blade
    • the underside of the leaf has hairs on it
    • the underside of the leaf has no hairs
    Hairs on upper side of leaf blade
    • the upper side of the leaf is fuzzy or hairy
    • the upper side of the leaf is not hairy, or has very few hairs
    Leaf blade base shape
    the base of the leaf blade is rounded
    Leaf blade base symmetry
    the leaf blade base is symmetrical
    Leaf blade bloom
    there is a noticeable powdery or waxy bloom on the underside of the leaf
    Leaf blade edges
    the edge of the leaf blade has teeth
    Leaf blade edges (Acer)
    NA
    Leaf blade flatness
    the leaf is flat (planar) at the edges
    Leaf blade hairs
    • at least some of the hairs on the leaf blade have glands at their tips
    • the hairs on the leaf blade are different from the choices given
    • the leaf blade has tangled or woolly-looking hairs, without glands
    Leaf blade length
    25–70 mm
    Leaf blade scales
    there are no scales on the leaf blades
    Leaf blade shape
    • the leaf blade is elliptic (widest near the middle and tapering at both ends)
    • the leaf blade is obovate (egg-shaped, but with the widest point above the middle of the leaf blade)
    • the leaf blade is orbicular (roughly circular, as wide as long)
    Leaf blade texture
    • the leaf blade is coriaceous (has a firm, leathery texture)
    • the leaf blade is herbaceous (has a leafy texture)
    Leaf blade translucent dots
    there are no translucent dots on the leaf blade
    Leaf blade vein pattern
    the main veins of the leaf blade are pinnate (the secondary veins branch off at intervals from the main central vein) and non-arcuate (not arched towards the leaf tip)
    Leaf blade veins
    the leaf blade has one main vein running from the base toward the tip
    Leaf blade width
    10–50 mm
    Leaf duration
    the leaves drop off in winter (or they wither but persist on the plant)
    Leaf form
    the plant is broad-leaved (with broadly flattened leaf blades)
    Leaf lobe tips (Quercus)
    NA
    Leaf midrib glands
    • the midrib of the leaf blade has glands on the upper surface
    • the midrib of the leaf blade lacks glands on the upper surface
    Leaf stalk
    the leaves have leaf stalks
    Leaf stalk attachment to leaf
    the petiole attaches at the basal margin of the leaf blade
    Leaf stalk nectaries
    there are no nectaries on the leaf stalk
    Leaf stalk shape
    the leaf stalk is not flattened
    Leaf teeth
    • the leaf blade margin is crenate (with rounded teeth) or crenulate (with tiny, rounded teeth)
    • the leaf blade margin is serrate (with forward-pointing) or dentate (with outward-pointing) with medium-sized to coarse teeth
    Leaf teeth hairs (Carya)
    NA
    Leaf type
    the leaf blade is simple (i.e., lobed or unlobed but not separated into leaflets)
    Leaves per node
    there is one leaf per node along the stem
    Specific leaf type
    the leaves are simple (i.e., lobed or unlobed but not separated into leaflets
    Stipules
    the plant has stipules

  • Place

    Habitat
    • terrestrial
    • wetlands
    New England state
    • Connecticut
    • Maine
    • Massachusetts
    • New Hampshire
    Specific habitat
    • fens
    • shores of rivers or lakes
    • swamps

  • Scent

    Plant odor
    the plant does not have much of an odor, or it has an unpleasant or repellant odor

  • Stem, shoot, branch

    Aerial roots
    the plant has no aerial roots
    Bark texture
    the bark of an adult plant is thin and smooth
    Branch brittleness (willows only)
    NA
    Branch cross-section
    the branch is circular in cross-section, or it has five or more sides, so that there are no sharp angles
    First-year cane (Rubus)
    NA
    Lenticels on twigs
    there are clearly lenticels on the twigs
    Short shoots
    there are peg- or knob-like shoots present
    Twig bloom
    there is no bloom on the twig
    Twig hairs
    • the twigs have hairs with glands at their tips
    • the twigs have hairs, but the hairs do not have glands
    Twig papillae (Vaccinium species only)
    NA
    Twig scales
    there are no scales on the twig surface
    Twig winter color
    • brown
    • gray
    • purple
    • red
    Wings on branch
    the branch does not have wings on it
    armature on plant
    the plant does not have spines, prickles, or thorns

Wetland status

Occurs only in wetlands. (Wetland indicator code: OBL)

In New England

Distribution

Connecticut
present
Maine
present
Massachusetts
present
New Hampshire
present
Rhode Island
absent
Vermont
absent

Conservation status

Exact status definitions can vary from state to state. For details, please check with your state.

Connecticut
rare (S-rank: S2), threatened (code: T)
Maine
rare to uncommon (S-rank: S2S3), special concern (code: SC)
Massachusetts
extremely rare (S-rank: S1), endangered (code: E)
New Hampshire
extremely rare (S-rank: S1), endangered (code: E)

From Flora Novae Angliae dichotomous key

11.  Betula pumila L. N

bog birch. Betula glandulifera (Regel) Butler; B. glandulosa Michx. var. glandulifera (Regel) Gleason; B. pumila L. var. glandulifera Regel; B. pumila L. var. renifolia Fern. • CT, MA, ME, NH. Fens, Evergreen swamps dominated by Thuja occidentalis, fen-like lake and stream shores in high-pH bedrock regions. Reports of this species from VT are based on hybrids with Betula pumila.

7×11. Betula papyrifera × Betula pumila → Betula ×‌sandbergii Britt. is a rare hybrid that occurs in VT. It is a shrub or small tree with dark red-brown, close bark. The oval to ovate leaf blades are 2.5–6.5 cm long with serrate margins, acute at the apex and cuneate at the base. The body of the samara is wider than its individual wings.

Native to North America?

Yes

Sometimes confused with

Betula glandulosa:
leaf blades 0.5-3 cm long, branchlets with abundant, large resin glands, and plants of alpine areas (vs. B. pumila, with leaf blades mostly 2.5-5 cm long, branchlets without resin glands or with few, small glands, and plants of fens and swamps).

Synonyms

  • Betula glandulifera (Regel) Butler
  • Betula glandulosa Michx. var. glandulifera (Regel) Gleason
  • Betula pumila L. var. glandulifera Regel
  • Betula pumila L. var. renifolia Fern.

Family

Betulaceae

Genus

Betula