Prunus spinosa


 * Blackthorn redirects here; for other uses, see Blackthorn (disambiguation)

Prunus spinosa (Blackthorn) is a species of Prunus native to Europe, western Asia, and locally in northwest Africa.

It is a deciduous large shrub or small tree growing to 5 m tall, with blackish bark and dense, stiff, spiny branches. The leaves are oval, 2–4.5 cm long and 1.2–2 cm broad, with a serrated margin. The flowers are 1.5 cm diameter, with five slightly creamy-white petals; they are produced shortly before the leaves in early spring, and are hermaphroditic and insect-pollinated. The fruit, called a "sloe" (slae, in the Scots language) is a drupe 10–12 mm diameter, black with a pale purple-blue waxy bloom, ripening in autumn; it is thin-fleshed, with a very strongly astringent flavour when fresh.

It is frequently confused with the related Prunus cerasifera, particularly in early spring when the latter starts flowering somewhat earlier than P. spinosa. They may be distinguished by flower colour, creamy white in P. spinosa, pure white in P. cerasifera. They can also be distinguished in winter by the more shrubby habit with stiffer, wider-angled branches of P. spinosa, and in summer by the relatively narrower leaves of P. spinosa, more than twice as long as broad.

Ecology
The foliage is sometimes eaten by the larvae of Lepidoptera including Emperor Moth, Common Emerald, November Moth, Pale November Moth, Mottled Pug, Green Pug, Brimstone Moth, Feathered Thorn, Brown-tail, Yellow-tail, Short-cloaked Moth, Lesser Yellow Underwing, Lesser Broad-bordered Yellow Underwing, Double Square-spot and the Black and Brown Hairstreaks.

Cultivation and uses
The fruit is similar to a small damson or plum, suitable for preserves, but too tart and astringent for eating, unless deeply frozen, as is practiced in eastern Europe. In rural Britain so-called sloe gin is made from them, though this is not a true gin but a liqueur. In Navarra, Spain, patxaran is a popular liqueur made with sloes. Sloes can also be made into jam and, if preserved in vinegar, are similar in taste to Japanese umeboshi.

It is extensively planted for hedging and for cover for game birds. The small thorns of the plant are relatively common causes of minor wounds in livestock, and these wounds often suppurate until the thorn is expelled or removed.

Straight blackthorn stems have traditionally been made into walking sticks, and in Ireland for making shillelaghs, a club-like weapon.

The species is locally naturalised in New Zealand and eastern North America.

A "sloe-thorn worm" used as fishing bait is mentioned in the 15th century work, The Treatyse of Fishing with an Angle, by Juliana Berners.

The expression "sloe-eyed" for a person with dark eyes comes from the fruit, and is first attested in A.J.Wilson's 1867 novel Vashti.