Alder
Alnus glutinosaAlder grows by rivers and on wet ground. Its leaves are dark and rounded, and small woody cones hang on its twigs in every month of the year.
How to identify alder →
Chase Mathey, CC BY 4.0
Jens-Christian Svenning, CC BY 4.0
Lookalikes
Alder or downy birch?
Both grow on wet ground, and both hang catkins in spring.
The quickest check
The quickest check is the older trunk. Alder: brown, cracked into small deep square plates. Downy birch: dull greyish white, with grey bands across.
At a glance
| Look at | Alder | Downy birch |
|---|---|---|
| Older trunk | Brown, cracked into small deep square plates | Dull greyish white, with grey bands across |
| Outline of a leaf | Racquet-shaped, the tip rounded or notched | A rounded triangle, 2 to 5 cm long |
| Ripe fruit on a twig | Small woody cones, on the tree all year | Hanging catkins that break apart when ripe |
Three ways to tell them apart
Older trunkBark
Outline of a leafLeaves
Ripe fruit on a twigCones
The two trees
Downy birch
Betula pubescensDowny birch is a slender, upright tree, often on wet, poorly drained ground. Its bark is dull greyish white, banded with grey. Its young shoots feel velvety, covered in very short hairs.
How to identify downy birch →Their other lookalikes
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: Chase Mathey (CC BY 4.0), Jens-Christian Svenning (CC BY 4.0), Jan Sheppard (CC BY 4.0), bobwardell (CC0), steve_mcwilliam (CC0), Barry Walter (CC BY 4.0). With thanks to everyone who shares their photographs on iNaturalist and Wikimedia Commons.