Prunus spinosa aka Blackthorn

Prunus spinosa, known as blackthorn or sloe, belongs to the rose family. It grows as a thorny shrub or small tree. Its native range spans Europe, western Asia, and northwest Africa. It is native to Britain and Ireland. Wild plants grow in hedges and woods, often in sunny spots. They grow on many soils, but not acid peat.

In gardens, blackthorn reaches about 8–13 feet [2.5–4 metres] tall and wide. It may take 20–50 years to reach full size. Its bushy growth can form a dense hedge or thicket. Shoots from the roots can spread beyond the main plant. These suckers can become a nuisance where space is tight. Remove them unless a spreading thicket suits the site. The dark green leaves are oval and fall in autumn.

Small white flowers open in early to mid-spring. Dark, egg-shaped fruits follow, each with a pale, waxy coating. These sloes measure about 0.6 inches across and hold one large seed. Their flesh tastes very sharp and makes the mouth feel dry. Frost makes the taste less harsh, though most people cook them. Uses include jelly, syrup, preserves, and flavouring for gin and other drinks. In France, people also pickle the unripe fruit. The flowers can be sugared, and dried fruit goes into herbal teas.

Grow blackthorn in full sun with moist soil that drains well. It accepts chalk, clay, loam, and sand. Acid, neutral, and alkaline soils all suit it. The RHS rates it H7 for cold tolerance. PFAF lists USDA zones 4–8. It suits coastal sites, wildlife gardens, screens, and informal planting. Its dense growth also serves as a living fence or windbreak. The bark supplies tannin and ink. Leaves, fruit, and bark can yield dyes. Propagate it from seed or softwood cuttings taken in early summer.

Aphids, caterpillars, and bullfinches can damage blackthorn. Silver leaf and blossom wilt may also affect it. It is a high-risk host for Xylella fastidiosa. Where silver leaf causes trouble, the RHS advises pruning in midsummer. The fruit flesh has food uses, but the seed kernels are harmful if eaten. The RHS also warns of harm to dogs, rabbits, and rodents. Do not treat the edible flesh as proof that all parts are safe.