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🫐 Sloe (Blackthorn) Prunus spinosa

Hedgerow · season: Flowers March-April; fruit picked September-November, traditionally after the fi · recorded as likely at 21 spots

Never eat anything you cannot identify with 100% certainty.

This is a guide, not a substitute for expert identification. Foraging guides - including this one - can contain errors. If you are not completely certain of an identification, do not eat it. Cross-check against at least two independent sources, and when in doubt, consult a local foraging expert or an experienced forager in person before eating anything wild.

The small, blue-black, tart fruit of blackthorn, a dense thorny hedgerow shrub, traditionally picked after the first frost for sloe gin and jellies.

Identification

Blackthorn is a dense, thorny deciduous shrub or small tree, typically 2.5-4m, with smooth dark brown-black bark. Its defining feature: it flowers before the leaves appear - clouds of small, five-petalled white blossom cover bare, dark branches in March-April, well ahead of hawthorn, which leafs first and flowers later. Leaves, once out, are small (2-4.5cm), oval to obovate with a finely toothed margin. The branches carry long, sharp, rigid spines (modified side-shoots) rather than the small curved prickles of rose or bramble. Fruit (sloes) are round, 10-15mm, blue-black with a pale waxy bloom, ripening August-October; the flesh is very astringent and sour raw.

⚠️ Dangerous look-alikes - read this before picking anything

The main confusable species is bullace/wild plum (also Prunus, sometimes classed as P. domestica subsp. insititia) - this is edible, not a toxic-risk confusion, but worth flagging: bullace and other wild plums bear noticeably larger fruit, have broader leaves, and the trees typically lack blackthorn's spines. As noted above, thorns present before/with the leaves and flowering on bare wood in early spring are the reliable blackthorn giveaways. The genuine safety point is about the stones, not the fruit: sloe stones (kernels), like the pips/kernels of other Prunus species (cherry, plum, apricot, peach), contain amygdalin, a cyanogenic glycoside that releases hydrogen cyanide only if the kernel is crushed/chewed and the enzyme content is released - this is confirmed by poison-control and food-science sources. Whole, unchewed stones swallowed incidentally (e.g. in sloe gin, where fruit is left whole) are not a practical hazard. Do not deliberately crush, chew, or blend sloe stones/kernels into food, and don't eat sloe kernels in any quantity.

UK habitat

Very common throughout the UK in hedgerows, woodland edges and scrubland, tolerant of most soils.

Legal notes

Picking sloes from wild blackthorn is covered by Theft Act 1968 s4(3) - fruit from a wild plant, non-commercial, is not theft. Don't uproot the shrub without landowner permission (Wildlife and Countryside Act 1981 s13). Blackthorn (Prunus spinosa) is not on WCA 1981 Schedule 8. See the full UK foraging law guide for the general rules.