Side by side

Ash or box elder? How to tell them apart

Fraxinus excelsior · Acer negundo

How to tell them apart – ash: more leaflets (7–13) and thick black buds; box elder: only 3–5 leaflets and green twigs.

Updated on 10 October 2026

Photo: No machine-readable author provided. JoJan assumed (based on copyright claims)., CC BY-SA 3.0 · source

Ash Fraxinus excelsior

Photo: Herman, D.E. et al. 1996. North Dakota tree handbook. USDA NRCS ND State Soil Conservation Committee, Public domain · source

Box elder Acer negundo

How do you recognise them?

Ash: Opposite pinnate leaves with 9–13 leaflets and thick, matt black buds.; Compared with box elder: more leaflets (7–13) and thick black buds.
Box elder: Maple with compound leaves of 3–5 leaflets and green, white-bloomed twigs.; Compared with ash: only 3–5 leaflets and green twigs.

Ash and box elder side by side
	Ash	Box elder
Leaves	Opposite, pinnate with 9–13 oblong, toothed leaflets. The leaves often fall while still green in autumn.	Opposite, pinnate with 3–5 (sometimes 7) coarsely toothed or slightly lobed leaflets.
Flowering	April	March–April
Fruit	Clusters of winged fruits (‘keys’) that hang on well into winter.	Paired winged fruits in long hanging clusters.
Bark	Smooth and greenish-grey when young, later pale grey with a fine network of ridges. Buds velvety black.	Young twigs green, often with a blue-white bloom; older bark grey-brown, shallowly fissured.
Shape and height	Broadleaf tree, 20–35 m	Broadleaf tree, 10–20 m
Site	Sun or partial shade, any garden soil, moist to wet	Sun or partial shade, any garden soil, normal
Native to Belgium	Yes	No, naturalised
Good for bees, butterflies and birds	Yes, for butterflies and birds	Little
Poisonous to people and pets	Not known to be poisonous	Not known to be poisonous
Pruning months	November–March	July–October

Ash is native: it feeds more insects and birds than a non-native species. If in doubt, choose this one.
Ash (20–35 m) and box elder (10–20 m) both grow into large trees: too big for an ordinary garden, but fine in a large garden, a park or a meadow.