Photo: Martin Olsson (mnemo on en/sv wikipedia and commons, martin@minimum.se) · CC BY-SA 3.0 ↗

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ShrubsWild and cultivated

Prunus spinosa

Blackthorn

White blossom usually appears before the leaves, followed by bloom-covered blue-black sloes in autumn.

See all four seasons Explore fruits, seeds & edibility ↓ Where to look & how to find it ↓

Some plants are poisonous. Do not identify by a photograph alone, and never taste them.

FIELDCRAFT · FIND WITH CARE

Finding guide

Season first

Choose the season, find the habitat, then watch patiently. Search guidance is not a measure of rarity or conservation status.

When to go: Usually flowers March–May; fruits ripen in autumn.
Where to start: Irish field boundaries. Compare its flowering sequence and leaf shape with later-flowering hawthorn.
What to do when you arrive: In early spring, look for white flowers on leafless hedges, then revisit for small leaves, long thorns and blue-black autumn fruits. Do not cross thorny hedges or break fruiting branches.

Habitat and behaviour reference: Wildflowers of Ireland ↗ · The practical steps are editorial advice based on the references, not live sightings.

ONE PLANT · FOUR SEASONS

One plant. Four seasons.

Look beyond the flowers: fresh leaves, fruits, bare stems and dormancy.

Meteorological seasons: spring March–May, summer June–August, autumn September–November and winter December–February. Irish weather, cultivar, pruning and plant age affect timing and appearance.

Photos illustrate the relevant feature, not the same plant photographed through a year in Ireland. Features shared across seasons, such as evergreen leaves, may use the same reference. Missing reliable photos are marked; dormancy is not death.

Spring

Mar–May

Flowers

White blossom usually precedes the leaves, contrasting strongly with dark thorny shoots.

Summer

Jun–Aug

Foliage and growth

Small oval green leaves cover the branches while young sloes develop.

Autumn

Sep–Nov

Fruits

Blue-black bloom-covered sloes accompany yellowing and falling leaves.

Winter

Dec–Feb

Bare branches or dry stems

Dark thorny twigs are clear after leaf fall, sometimes retaining a few fruits.

Seasonal references: Wildflowers of Ireland ↗ · Photo resized, converted to JPEG and stripped of metadata.

FRUIT · SEED · FOOD SAFETY

Fruits, seeds & edibility

Know the structure, then the part. Recognising a plant does not make it food.

Fruit

Blackthorn · Blue-black, plum-like drupes on the branches. — Blue-black, plum-like drupes on the branches.
AlexandreAssatiani · CC BY 4.0 ↗ License terms

Rounded blue-black drupes carry a waxy bloom and are known as sloes.

Food use of this part: Food use concerns the flesh, not stones or kernels

Seeds & dispersal units

Blackthorn · The hard stone enclosing the seed, not an edible kernel. — The hard stone enclosing the seed, not an edible kernel.
Tracey Slotta, USDA-NRCS PLANTS Database · Public domain ↗

Each fruit has one hard stone enclosing the seed; do not chew the stone or eat the kernel.

Food use of this part: Do not eat

Some seed references show intact one-seeded fruits or dispersal units, as identified in their captions. A whole-fruit photo is not a close-up of the enclosed seed. Cones and arils are not true fruits of flowering plants.

Sources & limitations

Wildflowers of Ireland ↗ · Botanical description, not proof of food safety
RHS · Prunus spinosa ↗
Woodland Trust · Rose hips, sloes and haws ↗

No field detoxification methods or safe doses are provided. Never taste a plant to identify it or eat treated or contaminated specimens. Seek professional help after suspected accidental ingestion. National Poisons Information Centre, Ireland ↗

Photo resized, converted to JPEG and stripped of metadata.

BOTANICAL NOTESPlant notes

How to identify it

Dark thorny branches, finely toothed oval leaves and five-petalled white flowers usually preceding the foliage; rounded fruits follow.

Where it grows

Hedgerows, scrub, field boundaries and woodland edges.

Growth and ecology

A deciduous spiny shrub spreading by suckers; blossom and dense branches support insects and birds.

Flowering and seasons

Usually flowers March–May; fruits ripen in autumn.

Where to look

Irish field boundaries. Compare its flowering sequence and leaf shape with later-flowering hawthorn.

Seasons vary with weather and location. Suggested habitats are places to look, not guaranteed sightings. Photos show only some features; check leaves, flowers, fruits and specialist references together.

Further reading:Wildflowers of Ireland ↗

Photo license: Martin Olsson (mnemo on en/sv wikipedia and commons, martin@minimum.se) · CC BY-SA 3.0 ↗ · License terms ↗
Photo resized, converted to JPEG and stripped of metadata.

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