Prunus spinosa, called blackthorn or sloe, is a species of flowering plant in the rose family Rosaceae. It is native to Europe, western Asia, and in northwest Africa. Blackthorn usually grows as a bush but can grow as a tree to a height of 6 m.
Prunus spinosa is a large deciduous shrub or small tree growing to 5 metres (16 ft) tall, with blackish bark and dense, stiff, spiny branches. The fruit, called a "sloe", is a drupe 10–12 millimetres (3⁄8–1⁄2 in) in diameter, black with a purple-blue waxy bloom, ripening in autumn and harvested – traditionally, at least in the UK – in October or November after the first frosts. Sloes are thin-fleshed, with a very strongly astringent flavour when fresh. The specific name spinosa is a Latin term indicating the pointed and thornlike spur shoots characteristic of this species. The common name "blackthorn" is due to the thorny nature of the shrub, and possibly its very dark bark: it has a much darker bark, than the white-thorn (hawthorn), to which it is contrasted.