Spiny shrub of roadside and hedgerow, blackthorn forms dense scrub cover where it is left untrimmed and ungrazed.
It bears dense clusters of small white flowers, which contrast with the dark bark of its twigs, very early in the year. Blackthorn hedges can appear to be covered in white.
After the flowers, the small oval leaves appear, and then in autumn the harvest of sloes develops. These look like small damsons, but are very sour and are not eaten directly by people, although birds take them. Sloes have traditionally been used for flavouring gin or poteen. The use of blackthorn wood is mainly decorative, for example the manufacture of shillelagh walking sticks and tourist souvenirs.