Blackthorn

What does Blackthorn look like?

Blackthorn grows as a dense, thorny shrub or sometimes a small tree, reaching up to 5 or 6 metres tall. Its bark is very dark, almost black, and the branches are stiff and tangled with sharp spines. In early spring, before the leaves appear, it produces clusters of small, creamy-white flowers, each with five petals. The leaves are oval and finely toothed. By autumn, the plant bears small, round fruits called sloes, which are blue-black with a waxy coating and contain a single stone inside.

Where does Blackthorn come from?

Blackthorn is native to Europe and West Asia, and also grows in parts of northwest Africa. Over time, it has spread and become established in regions like Tasmania and eastern North America. The name 'spinosa' refers to its thorny shoots, while 'blackthorn' points to its dark bark. The fruit name 'sloe' has roots in old Germanic and Slavic languages, often linked to plums. Archaeological finds show people have eaten sloes since ancient times, including in the Alps over 5,000 years ago.

When and how Blackthorn blooms

Blackthorn flowers appear in early spring, just before the leaves open. The plant thrives in temperate climates and is often found in hedgerows, woodland edges, and scrubby areas. It can be grown from seed or by planting young shrubs. The fruit ripens in late autumn, usually after the first frosts, which soften their skin and make them easier to use for preserves and drinks.

How Blackthorn is used

Sloes are picked in autumn and used to make drinks like sloe gin in Britain and pacharán in Spain. The fruit also goes into jams, chutneys, and pies, and can be preserved in vinegar. Its juice can dye fabric, and the leaves were once mixed with tea. The tough wood is shaped into walking sticks, especially the Irish shillelagh, and tool handles. In Britain and Ireland, blackthorn is also planted as a natural hedge.

Kinds of Blackthorn

Blackthorn is sometimes mistaken for the cherry plum, which flowers earlier and has larger blossoms and different fruit colours. The two can be told apart by flower size, leaf shape, and fruit colour. There are no widely grown named varieties of blackthorn, but local traditions and uses vary across Europe.

What Blackthorn means

In the UK, 'blackthorn winter' describes a cold snap during its spring bloom. The flowering is linked to the Celtic festival of Imbolc in parts of Ireland and Scotland. Sloe fruit has inspired phrases like 'sloe-black eyes' in English literature. The wood is traditional for Irish walking sticks and is carried by officers in some Irish regiments. Sloe juice has also been used to dye cloth and as an ingredient in ink.

Where Blackthorn is used and seen

Eastwoodhill ArboretumNew Zealand’s national arboretum with thousands of trees from around the world

Questions people ask about Blackthorn

Good reading and sources

• Encyclopaedia BritannicaArticle
• IUCN Red List of Threatened SpeciesIUCN Red List, Article
• USDA Plants DatabaseUS Department of Agriculture, Article
• Prunus spinosaRoyal Horticultural Society, Article
• Plants of the World OnlineRoyal Botanic Gardens, Kew, Plant database
• Where it has been recordedGBIF, Plant database
• Sightings and photos by naturalistsiNaturalist, Plant database

• Prunus spinosa on WikipediaEncyclopedia
• More photos on Wikimedia CommonsPhotos
• Wikidata recordOpen data