Hawthorn vs blackthorn: how to tell the two hedgerow thorns apart

Blossom: before the leaves or after

This is the test most people need, because both hedges turn white in spring.

Blackthorn flowers first, on bare wood. The Woodland Trust gives March and April, with the flowers appearing before the leaves. They are white and star-shaped, on short stalks, singly or in pairs, so a flowering blackthorn hedge looks like a white haze over black twigs, with no green at all.

Hawthorn flowers in May, after the leaves. Its leaves are often among the first to appear in spring, so by the time it blooms the hedge is green. The flowers are white or occasionally pink, with five petals, highly scented, and grouped in flat-topped clusters. May is where its name May tree comes from.

So: white with no leaves in March or early April is blackthorn; white among leaves in May is hawthorn. The one complication is Midland hawthorn (Crataegus laevigata), which the Woodland Trust says flowers from mid-April, one to two weeks before common hawthorn, but still after its leaves. Our hawthorn page covers how to tell the two hawthorns apart.

If you have only a blurry memory of a hedge in flower, Tree Identifier can suggest a name from a photo of one flowering twig. It gives no confidence score and no list of alternatives, so check for leaves in the picture: their presence or absence is the clue the photo has to show.

Fruit: sloes and haws

In autumn the hedges carry fruit of different colours.

• Sloes are blackthorn's fruit: blue-black, about 1 cm across. The Woodland Trust notes they are eaten by birds in autumn and that sloes are an ancestor of cultivated plums.
• Haws are hawthorn's fruit: deep red, following the flat-topped flower clusters, with a single seed in each. A haw with two seeds belongs to Midland hawthorn.

Sloes are best known as the fruit steeped in gin to make sloe gin, which the Woodland Trust calls a favourite wintry tipple. This page does not cover picking or preparing them. For other red fruits of British hedges, from rowan to holly, see our guide to identifying British trees.

Thorns, twigs and bark in winter

With no leaves, flowers or fruit, go to the twig.

Where the bud sits. The Woodland Trust's winter test: hawthorn's spines emerge from the same point as its buds, while blackthorn has its buds on the spines themselves. On blackthorn, straight side shoots grow out and harden into thorns, and buds line them. On hawthorn, a spine and a bud sit side by side at the same spot on the twig.

Twig colour. Blackthorn twigs are black-purple, black and spiny in winter. Hawthorn twigs are slim and brown.

Bud arrangement. The Woodland Trust's How to Identify Trees guide groups hawthorn with the trees whose buds alternate along the twig, and blackthorn with the spiral group alongside the oaks.

Bark. Blackthorn bark is smooth and dark brown. Hawthorn bark is brown-grey, knotted and fissured, especially on old trees left to grow out of the hedge. Our winter tree identification guide covers reading buds and twigs on other trees.

Handle both with gloves. The Woodland Trust warns that blackthorn thorns can break off in the skin and cause infection or inflammation, sometimes days later.

Leaves, size and the name whitethorn

Leaves. Hawthorn leaves are about 6 cm long and deeply lobed, the lobes cut at least halfway to the midrib, turning yellow before they fall. Blackthorn leaves are small, oval, slightly wrinkled and toothed, pointed at the tip and tapered at the base, with no lobes. A lobed leaf on a thorny hedge shrub is hawthorn.

Size. Left uncut, hawthorn becomes a tree of up to 15 m. Blackthorn stays smaller: the Woodland Trust gives around 4 m in its quick facts and up to 7 m elsewhere on the same page. Blackthorn grows naturally in scrub, copses and woodland and is widely used as a hedging plant; it does best in full sun.

Whitethorn and blackthorn. Whitethorn is one of hawthorn's old names, listed by the Woodland Trust with May tree, quickthorn and one-seed hawthorn, so the pair is sometimes described as whitethorn and blackthorn. In winter the contrast is in the twigs: hawthorn's are brown, blackthorn's black-purple.

Both are native to Britain and appear on the Woodland Trust's list of native trees; our page on UK native trees gives one clue for each of the 45.

Cherry plum: the third white hedge in spring

Cherry plum (Prunus cerasifera) flowers white in early spring too and is often mistaken for blackthorn. The Woodland Trust gives three differences: cherry plum is usually thornless, it flowers as its leaves emerge rather than before them, and its twigs are hairless. Garden and ornamental cherries can also flower on bare wood; our cherry page covers them.