Aspen, Populus tremula, seed-bearing catkins in early spring, Cairngorms National Park


Would you be able to identify aspen while out walking? We want to make aspen as well-known and widely appreciated as oak, hazel and rowan!


Recognising aspen - size

Size and shape

  • Aspen is generally a slender tree, featuring a long trunk with perpendicular branches.
  • A medium-sized tree, aspen can grow to a height of 65ft, but is often stunted in exposed locations.

Bark and trunk

  • Aspen bark is typically creamy grey in colour, and often greyer at the base.
  • With age, it becomes pitted with bands of small black diamonds.
  • A greenish tinge to the bark hints at the trunk's ability to photosynthesise.
Recognising Aspen - bark
Recognising aspen - suckers


  • Clusters of long, whip-like suckers grow beside or near to an adult parent tree.
  • These suckers are genetic clones of the parent.
  • When small, saplings or suckers have triangular green, softly furred leaves.
  • At 6½ft in height, leaves become like those of the adult tree.


  • Leaves are rounded to slightly oval with curved marginal teeth.
  • Late to emerge and often have a red hue before turning green.
  • Mature leaves are green on both sides with a paler underside.
  • Leaves are attached by long, flattened petioles (stalks), which allow for their characteristic quivering/trembling.
  • In autumn, the leaves can at first turn various shades of red or orange but always come to be a bright yellow, perhaps the brightest yellow of any of our native trees.
  • Where many trees are present this can paint a whole landscape yellow.
Recognising Aspen - leaves
Recognising aspen - catkins


  • Catkins are either male or female. Both grow in clusters and can be up to 3in long.
  • Male catkins are floppy and a reddish/pale purple. These develop powdery yellow pollen before being cast from the tree in April.
  • Female catkins are firmer, fluffier and green but tinged with pink. These remain on the tree until late May/June once their seeds are dispersed.


Aspen leaves trembling in the breeze make a characteristic whispering sound.


Recognising aspen - listen