Prunus spinosa

People often confuse blackthorn and white thorn. Both are thorny and produce white flowers but there the similarity ends as they are two entirely separate species.   Country people know that an encounter with blackthorn is much more severe as it can inflict a septic splinter.


Blackthorn, which is also known as sloe — the name of its fruits, is a common, small tree of roadside and hedgerows.   However, if it is not regularly trimmed, it gradually extends from the hedgerows to colonise land which is under-grazed or abandoned.   Here it forms a dense scrub cover, which provides excellent protection from grazing animals for more tender species.

Early in the year, blackthorn bears dense clusters of small, white flowers, which contrast with the dark bark of its twigs.   It flowers profusely so that blackthorn hedges appear to be covered in white.   Appearing in March and often as early as February, they are the first harbingers of spring. After flowering, the small oval leaves appear, and in the autumn the sloe matures. These look like damsons, but are very sour.   Traditionally, sloes were used to flavour gin and poteen.   Blackthorn timber is used mainly to make decorative items, for example walking sticks, shillelaghs and other tourist souvenirs.

In the Brehon laws blackthorn was classified in the lower division of trees.   However, several townlands are named after An Draighean, the Gaelic word for blackthorn, for example Draighean, Dreenan, Drinane, and Drinaun or Aghadreenagh and Aghadreeen — the fields of blackthorn.   Some townlands are named after its fruits, the sloe, or airne in Gaelic, for example Killarney — the church of the sloe.   Best known is Killarney, Co Kerry but the townland name Killarney is also found in Co Kilkenny and in Bray, Co Wicklow.

There are no height records for blackthorn in the Tree Register of Ireland.

John Mc Loughlin
Tree Council of Ireland