Common ash
Fraxinus excelsiorAsh has an open, airy crown on slender, curving limbs. Its leaves usually have 9 to 13 leaflets, and sooty black buds sit in pairs on its grey shoots.
How to identify common ash →
Malc_l, CC BY 4.0
Mattia Menchetti, CC BY 4.0
Lookalikes
Common ash or tree of heaven?
Both have big feathered leaves: 40 to 60 cm on tree of heaven, 20 to 35 cm on ash.
The quickest check
The quickest check is the wing of a key. Common ash: flat and strap-shaped, with a blunt tip. Tree of heaven: narrow, twisted at both ends, seed halfway along. No keys on the tree? Check the edge of a leaflet.
At a glance
| Look at | Common ash | Tree of heaven |
|---|---|---|
| Wing of a key | Flat and strap-shaped, with a blunt tip | Narrow, twisted at both ends, seed halfway along |
| Edge of a leaflet | Toothed, the teeth uneven | Smooth, with 1 to 6 big teeth at the base |
| Winter bud | Sooty black, shaped like a squat cone | A tiny reddish dome over a heart-shaped scar |
Three ways to tell them apart
Wing of a keyKeys
Edge of a leafletLeaves
Winter budTwigs and buds
The two trees
Tree of heaven
Ailanthus altissimaTree of heaven is a tall town tree, especially common in London. Its huge leaves have a few big teeth at the base of each leaflet. Bruised, they smell foul.
How to identify tree of heaven →Their other lookalikes
Common ash or elder?Quickest check: the leaflets on one leaf→
Common ash or English oak?Quickest check: the older trunk→
Common ash or common beech?Quickest check: the older trunk→
Common ash or false acacia?Quickest check: the edge of a leaflet→
Common ash or honey locust?Quickest check: the leaflets→
Common ash or sycamore?Quickest check: the whole leaf→
Tree of heaven or elder?Quickest check: the whole plant→
Tree of heaven or false acacia?Quickest check: the base of a leaflet→
In the app
See them side by side in Treely
- Both trees, part by partLeaves, bark, buds, flowers and fruit, photographed through the year
- Every lookalike side by sideThe checks that settle it, for every pair people mix up
- A short round each dayUntil you can tell them apart at a glance
- The full GuideBoth trees written up in full, with where to find them
Free to download.
Every fact on this page is checked against the Collins Tree Guide, last in November 2026. Spotted something that looks wrong in front of a real tree? Tell us. How we check.
Photographs: Malc_l (CC BY 4.0), Mattia Menchetti (CC BY 4.0), Leon Cross (CC BY 4.0), steve_mcwilliam (CC0), Daniel Cahen (CC BY 4.0). With thanks to everyone who shares their photographs on iNaturalist and Wikimedia Commons.