Forestry Commission logo

Identifying ash trees

Ash leaves

Leaves

Young ash tree

Ash leaves are 'compound' leaves, which means they comprise several 'leaflets'.  They are lance shaped, with slightly toothed edges. Leaflets are arranged in pairs, with an odd one at the end.

Bark

Ash bark is smooth and grey with fissures that appear as it grows older. The colour of the bark is thought to give the tree its name.

Buds

Ash flowers.

Distinctive black winter buds produce shoots and dense clusters of small purple flowers.

Flowers and seeds

Ash flowers and seeds can be male, female or both. The purple catkin female flowers ripen and grow into seeds called “keys”, so called because they look like old fashioned keys. They spin in the wind, so they are also called “spinners”.

Rowan (mountain ash) trees

Rowan leaves

Rowan trees are easily mistaken for ash, and in some places are called mountain ash, but they are not closely related to each other. (Rowan are members of the Sorbus genus; ash are members of the Fraxinus genus). Rowan trees are not susceptible to chalara ash dieback, and need not be reported.

Rowan leaves.

The main differences

  • Rowan leaves (as opposed to the leaflets) grow in staggered pairs on the twig, while ash leaves grow directly opposite each other, as seen in the top picture.
  • Rowan trees usually grow to only about 10 metres tall, whereas ash trees can grow to as high as 40m.
  • Rowan bark is purplish as opposed to the ash's greenish tint.
  • Where the ash has single-winged seeds in bunches, rowan has berries which ripen to a red colour.
Last updated: 18th December 2017