Sycamore vs Norway maple: how to tell them apart

Seeds: straight line or narrow V

Maple seeds come in pairs, each with a wing, and the angle between the wings is the classic way to tell these two apart. The Woodland Trust names it as the difference between the species: Norway maple's seeds sit at a wider angle than sycamore's.

• Norway maple: NatureSpot describes the wings as held at only a slight angle from a straight line; Virginia Tech's Norway maple fact sheet says they spread widely, measure about 4 to 5 cm (1 1/2 to 2 in) and ripen in late summer, often staying on the tree into winter.
• Sycamore: the Woodland Trust calls its seeds V-shaped with a narrower angle. Oregon State's sycamore maple page puts the angle at about 60 degrees and the samaras at 3 to 5 cm, in hanging clusters. NatureSpot describes the wings as at right angles; either way they form a clear V, not a line.

Seeds lie under both trees through autumn, which makes this the best test in late summer and autumn, when the sap can be hard to see in old, leathery stalks.

Flowers in spring

The two trees flower at different times, which makes April and May an easy season for this pair.

• Norway maple flowers first. Virginia Tech describes bright yellow-green, fairly conspicuous flowers that open before the leaves, and Oregon State places them in early spring. The Woodland Trust counts up to 30 flowers in a cluster. A street tree glowing lime-green on bare twigs in early spring is very likely a Norway maple.
• Sycamore flowers after its leaves have opened. Oregon State describes small yellow-green flowers in hanging clusters 8 to 12 cm long, and the Woodland Trust calls them green-yellow spikes, or racemes. They dangle among the leaves like tassels.

Bark, twigs and winter

In winter the leaves are gone and the trees look alike, so start with the bark and the twigs.

• Bark. The Woodland Trust's sycamore profile describes dark pinkish-grey bark, smooth when young and cracking into small plates with age; Oregon State says it flakes in small rectangular scales. Norway maple bark is grey with fine ridges, and Virginia Tech adds that older trees have shallow furrows with long, narrow ridges that partly interlace. Plates point to sycamore, a net of fine ridges to Norway maple.
• Twigs. Sycamore twigs are pinkish-brown and hairless. Norway maple twigs are slender and brown with tiny white spots, and its winter buds are green and red, according to the Woodland Trust.
• Leftover seeds. Norway maple seeds often hang on into winter with their wings nearly straight.

Buds are a weak test here: Oregon State notes that sycamore buds resemble Norway maple's. For more trees to name from twigs, bark and leftover fruit, see the UK tree identification guide.

Purple and coloured forms

Both species come in purple and patterned garden forms, and these are the leaves most likely to fool a photo.

• Crimson King is a Norway maple with dark purple leaves, nearly black according to Virginia Tech. Oregon State describes its autumn colour as maroon to reddish bronze. The purple runs through both sides of the leaf.
• Purple sycamore, Acer pseudoplatanus 'Atropurpureum', has leaves dark green above and purple beneath, Oregon State says. From below, the crown looks purple; from above, green.
• Brilliantissimum is a sycamore whose new leaves open shrimp-pink, then turn pale yellow-green and finally light to medium green, according to Oregon State.

Turn a leaf over before deciding, and squeeze the stalk: the milky sap works on every Norway maple cultivar.

Where each one grows

The Woodland Trust gives sycamore's native range as central, eastern and southern Europe. It may have been brought to Britain by the Romans or in the 1500s, spread widely from the mid-1800s and now grows across the UK, colonising woods where it can crowd out native trees. It reaches about 35 m and can live around 400 years. The sycamore page covers its history and the other tree, the American plane, that shares its name. In North America, sycamore means a plane tree; sycamore vs maple compares it with the American maples.

Norway maple is native to eastern and central Europe and was introduced to the UK in the 17th century. It grows to about 25 m and is found mainly as a street and park tree, valued, the Woodland Trust says, for its tall trunk and its tolerance of compacted soil, shade and pollution. Oregon State notes that in North America it seeds heavily and has spread into woodlands near cities, especially in the northeastern US; the Norway maple vs sugar maple page covers that pairing.

If neither tree fits and the leaf is small and rounded, check the native field maple. Tree Identifier can name a maple from one photo of a leaf, the bark or a seed cluster; it shows no confidence score or alternatives, so confirm with the sap and the seed angle. Norway maple is in the app's 138-species Collection; the British sycamore is not.