Dwarf Birch

Betula nana
© Copyright: Jouko Lehmuskallio
    • Growing form and height

      Shrub or dwarf shrub. 0.2–0.8 m (7–30 in.).

    • Flower

      Small, greenish to brownish, lacking perianth. Inflorescences dense, pendent catkins formed by numerous, 3-flowered cymes. Male and female flowers in separate inflorescences.

    • Leaves

      Fairly small, more or less orbicular (roundish), thick, hairless, margins crenate (with rounded teeth). Autumn colour yellow, orange, or red.

    • Buds

      Roundish, small, dark brown, scales hairy-edged.

    • Fruit

      Small, winged achene.

    • Habitat

      Bogs, swamps, fens. In Northern Finland also forests and mountain heaths.

    • Flowering time

      May–June. Flowers when coming into leaf.

    The genus Betula comprises some 40 species, both trees, shrubs, and dwarf shrubs. The trunks of birches are covered with white or darkish, often papery bark. Birches flower when coming into leaf in the spring. The small flowers are unisexual, the inflorescence a catkin-like, dense compound cyme.

    In Southern Finland, dwarf birch is wholly a mire plant thriving on many different mire types. It hybridises with both silver birch (B. pendula) and downy birch (B. pubescens). The hybrids are usually taller than pure dwarf birches and their leaves are larger. Dwarf birch used to be an important source for fuel in Lapland as it burns even when fresh. It is also a constituent part of the vivid autumn colours of the Lappish moorlands.

    Other species from the same genus (2)

    Distribution map: Lampinen, R. & Lahti, T. 2021: Kasviatlas 2020. Helsingin Yliopisto, Luonnontieteellinen keskusmuseo, Helsinki.

    Other species from the same genus (2)