Blackthorn is a spiny shrub with dark brown bark and small, oval, slightly wrinkled leaves with serrated edges. It usually forms a bush, but can grow to become a tree with a height of up to 6 or 7 metres.

The flowers are white with five petals, and appear shortly before the leaves in March or April. The fruit, known as a sloe, is black with a waxy dark blue or purple bloom. They are harvested in October or November after the first frosts.

Blackthorn is widespread across the UK. It grows in copses and woodland but is most often used as a hedging plant along the edges of fields and paths.