Plant Profile

BlackthornPrunus spinosa

The blackthorn (Prunus spinosa) is a native, thorny shrub known for its tart fruits. These are harvested after the first frost and are excellent for making jams, jellies, and liqueurs. Blackthorns are undemanding, robust, and provide habitat for insects and birds. They are well-suited for hedges and as a pioneer plant.

Wild plantsShrubsRose family
Calendar
Blackthorn (Prunus spinosa): plant portrait - Wild plants, Rose family, Harvest October - December
Blackthorn: plant portrait. harvest: October - December.

Quick profile

Key data

Growing calendar
JanFebMarAprMayJunJulAugSepOctNovDec
Direct sowing outdoors
Planting outdoors
Harvest
Pruning
Direct sowing outdoorsPlanting outdoorsHarvestPruning

Suitable growing locations:

Outdoor garden bedRaised bed

Good neighbors

English LavenderRosemaryGarden Strawberry

Avoid

tomatoCabbage (head cabbage)

Indoor & direct sowing

Blackthorn: Sowing and germination

Indoor sowing

No indoor sowing is necessary.

Direct sowing outdoors

Sow in autumn or early spring. Cold germinator.

Germination temp1 - 10 °C
Germination time30 - 90 days
Light germinatorNo
Dark germinatorNo
Cold germinatorYes
Stratification neededYes
Pre-soaking recommendedNo

Planting & site

Blackthorn: Planting and spacing

Planting outdoors

Plant young plants or cuttings in spring or autumn.

Soil pH5.5 - 7.5
Plant spacing150 - 300 cm

Site & practical notes

Blackthorns are extremely undemanding and easy to care for. They are excellent for naturalistic gardens, as bird protection shrubs, or for dense, thorny hedges. Harvesting the fruits requires caution due to the thorns. After the first frost, the fruits become milder and sweeter.

Temperature & frost

Blackthorn: Temperature and site

Growing temperaturefrom 5 °C
Optimal temperature15 - 25 °C
Max. heatup to 35 °C
Soil temperature1 - 5 °C
Frost sensitiveNo
Late frost sensitiveNo
Heat tolerancemedium
Cold tolerancevery high

Water & nutrients

Blackthorn: Water, nutrients and care

Waterlow
Critical water phasesEstablishment phase after planting
Droughtlow
Waterlogging sensitiveYes
Mulching recommendedNo
Nutrient needlight feeder
Compost recommendedNo
Fertilizer sensitivitylow

Container & growth

Blackthorn: Container, support and growth

Container suitableNo
SupportNo
Height200 - 500 cm
Width200 - 400 cm

Year plan

Blackthorn Calendar

Plants

After the first frost, the sloe berries become sweeter and are perfect for liqueurs and jams.

Year overview
JanFebMarAprMayJunJulAugSepOctNovDec
Direct sowing outdoors
Planting outdoors
Harvest
Pruning

Recurring tasks

Removal of unwanted root suckers and, if necessary, light corrections on hedges.July - August
Only as needed to control spread.
Harvesting sloesOctober - December
ripe: Harvest fruits after the first frost.

Relevant now

June

  • No additional single task

Next up

July

  • No additional single task

Monthly tasks

Single tasks from monthly data; repeated seasonal windows are shown in the overview above.

PlantingPruning

January

No additional single task

February

No additional single task

March

Formative and thinning prune, removal of old wood and disease sources.Pruning

Pruning

  • Formative and thinning prune, removal of old wood and disease sources.Prune before bud break, while the plant is dormant.
  • Pruningdormant season: Shaping and promoting fruit yield.

April

No additional single task

May

Quiet month

June

Quiet month

July

Quiet month

August

Quiet month

September

Quiet month

October

Pruning

Pruning

  • Pruningdormant season: Thinning and removal of dead shoots.

November

Planting cuttings or young plants

Planting

  • Planting cuttings or young plantsdormant season: Suitable for vegetative propagation.

December

No additional single task

Flowering & pollination

Blackthorn Flowering & pollination

Self-fertility

self-fertile

Pollinator needed

no

Overview

Blackthorns are predominantly self-fertile, but cross-pollination by other blackthorns or related species like plums can improve fruit set.

Notes

Bees, bumblebees, and other insects visit the flowers and contribute to pollination. The blossoms are also an important early food source for these insects.

Pruning & care

Blackthorn Pruning & care

Pruning type

Renewal pruning and structural pruning

Pruning timing

Late winter to early spring

Formative and thinning prune, removal of old wood and disease sources. Prune before bud break, while the plant is dormant.

Summer

Removal of unwanted root suckers and, if necessary, light corrections on hedges. Only as needed to control spread.

Remove

Dead, diseased, or damaged shoots.Crossing or rubbing branches.Inward-growing shoots.Root suckers if they interfere with the desired form.Overly dense shoots to improve ventilation.

Preserve

Strong, healthy main shoots.Fruiting wood (short shoots with fruit buds).An open, well-ventilated crown structure.The natural growth habit of the shrub.

Avoid

Radical shortening of healthy shoots that are not problematic.Pruning during frost.Excessive thinning that weakens the plant.Removal of all young shoots, as these form the fruiting wood.

Tools and hygiene

Clean and disinfect all cutting tools before and after use to prevent disease transmission.

Companion guide

Blackthorn Companion guide

Companion guide

Good neighbors

English LavenderRosemaryGarden Strawberry

Avoid

tomatoCabbage (head cabbage)

Use & storage

Blackthorn Use & storage

Harvest

Harvest fruits after the first frost to improve flavor.

Storage

Cool and dry, dark

Storage life

Fresh: a few days to 1 week. Frozen: up to 1 year. Dried: several months.

Harvest

Harvest fruits after the first frost to improve flavor.

Processing

JamJellyLiqueurJuiceDryingFreezing

After harvest

Fruits can be processed directly after harvest or stored in the refrigerator for a few days. Wash thoroughly before processing.

Notes

Freshly harvested fruits have limited shelf life. Preserved, dried, or frozen, they can be stored longer.

Edibility & safety

Blackthorn Edibility & safety

For people

In brief: which parts are edible, which parts remain risky, and whether raw consumption makes sense.

Edible parts:Fruit
Caution parts:Leaves, Seeds (contain small amounts of hydrocyanic acid)
Raw consumption:Raw consumption is only recommended in very small quantities or after frost, as the fruits are very tart and astringent. Processed, they are safe.

Safety notes

The seeds (kernels) of sloes contain amygdalin, which can be converted to hydrocyanic acid in the body. They should not be consumed. The fruits themselves are safe after processing or frost.

Animal safety

For animals, the specific plant part matters here: some parts may be suitable, while others should be avoided. At least one critical rating is listed for 11 animal types.

Animal safety by plant part

Each row shows which parts are more suitable and which parts are critical.

Companion animals

Dog icon for animal safety ratingDog

Fruit (after frost or processed)

No risk parts listed

usually no action needed

Fruits are suitable in small amounts for dogs as a treat after frost or processing. Leaves and seeds should be avoided as they contain amygdalin, which can be converted to hydrocyanic acid. No direct species-specific poisoning cases are known in dogs, but caution is advised.

Open animal page
Cat icon for animal safety ratingCat

Fruit (processed or after frost)

Leaves, Seeds

Risk factors

Consumption of unripe fruits, Consumption of seeds or leaves

Symptoms

Vomiting, Diarrhea, Abdominal pain

contact a vet if symptoms appear

The fruits of blackthorn can be given in small amounts as a treat, but leaves and seeds are toxic due to amygdalin (cyanide precursor) and should be avoided. If toxic parts are ingested, monitor for symptoms and seek veterinary advice if symptoms occur.

Open animal page
Rabbit icon for animal safety ratingRabbit

Fruit (processed or after frost)

Leaves, Seeds

Risk factors

Consumption of leaves or seeds, Unripe fruits

Symptoms

Diarrhea, Abdominal pain

contact a vet if symptoms appear

The fruit of blackthorn can be fed in small amounts as a treat, but leaves and seeds are toxic due to amygdalin (cyanide precursor) and should be avoided. If toxic parts are ingested, monitor for symptoms and contact a veterinarian if symptoms occur.

Open animal page
Guinea pig icon for animal safety ratingGuinea pig

Fruit (processed or after frost)

No risk parts listed

usually no action needed

No reliable species-specific assessment is available. Fruits might be considered in very small amounts as a treat after frost or processing, but leaves and seeds should be avoided due to amygdalin.

Open animal page
Hamster icon for animal safety ratingHamster

Fruit (processed or after frost)

No risk parts listed

usually no action needed

No reliable species-specific assessment is available. Fruits might be considered in very small amounts as a treat after frost or processing, but leaves and seeds should be avoided due to amygdalin.

Open animal page
Budgie icon for animal safety ratingBudgie

No suitable parts listed

No risk parts listed

unknown

No reliable species-specific assessment is available. Fruits might be considered in very small amounts as a treat after frost or processing, but leaves and seeds should be avoided due to amygdalin.

Open animal page

Farm animals

Horse icon for animal safety ratingHorse

Fruit (processed or after frost)

Leaves, Seeds

Risk factors

Consumption of unripe fruits, Consumption of seeds or leaves

Symptoms

Vomiting, Diarrhea, Abdominal pain

contact a vet if symptoms appear

The fruit of blackthorn can be fed in small amounts as a treat, but leaves and seeds contain amygdalin, which can be metabolized to cyanide. Poisoning is unlikely with normal fruit feeding, but possible if toxic parts are consumed.

Open animal page
Chicken icon for animal safety ratingChicken

Fruit (processed or after frost)

Leaves, Seeds

Risk factors

Seeds contain cyanogenic precursors, Leaves may be toxic

Symptoms

Vomiting, Diarrhea, Respiratory distress

contact a vet if symptoms appear

Fruits can be given in small amounts as a treat, but leaves and seeds are toxic due to amygdalin (cyanogenic precursor) and should be avoided. If toxic parts are ingested, observe for symptoms and contact a veterinarian if symptoms appear.

Open animal page
Duck icon for animal safety ratingDuck

Fruit (after frost or processing)

Seeds, Leaves

Risk factors

Consumption of large quantities of raw fruit, Consumption of seeds or leaves

Symptoms

Gastrointestinal disturbances, Cyanosis (in severe poisoning)

contact a vet if symptoms appear

The fruits are suitable as occasional treats after frost or processing. Seeds and leaves contain amygdalin, which can be converted to hydrogen cyanide and are therefore toxic. Raw consumption only in tiny amounts, as the fruits are astringent.

Open animal page
Goose icon for animal safety ratingGoose

Fruit (processed or after frost)

Leaves, Seeds

Risk factors

Seeds contain cyanogenic precursors, Leaves may be toxic

Symptoms

Vomiting, Diarrhea, Breathing difficulties

contact a vet if symptoms appear

The fruit of blackthorn can be fed as an occasional treat in small amounts after processing or frost. Leaves and seeds contain amygdalin, which can hydrolyze to hydrogen cyanide and cause gastrointestinal and respiratory symptoms. No species-specific studies exist for geese, but the compound is toxic to many animals. Caution is advised, especially with unripe fruit or damaged seed material.

Open animal page
Sheep icon for animal safety ratingSheep

Fruit (processed or after frost)

Leaves, Seeds

usually no action needed

No reliable species-specific assessment is available. Fruits might be considered in very small amounts as a treat after frost or processing, but leaves and seeds should be avoided due to amygdalin.

Open animal page
Goat icon for animal safety ratingGoat

Fruit (processed or after frost)

Leaves, Seeds

usually no action needed

No direct species-specific source was found for goats. This is a cautious inference from the sheep profile and the known plant-part risks. Fruits might be considered in very small amounts as a treat after frost or processing, but leaves and seeds should be avoided due to amygdalin.

Open animal page
Cattle icon for animal safety ratingCattle

Fruit (processed or after frost)

Leaves, Seeds

usually no action needed

No direct species-specific source was found for cattle. This is a cautious inference from the sheep profile and the known plant-part risks. Fruits might be considered in very small amounts as a treat after frost or processing, but leaves and seeds should be avoided due to amygdalin.

Open animal page
Pig icon for animal safety ratingPig

Fruit (processed or after frost)

Leaves, Seeds

Risk factors

Consumption of unripe fruits, Consumption of seeds or leaves

Symptoms

Vomiting, Diarrhea, Breathing difficulties

contact a vet if symptoms appear

Sloe fruits can be fed as an occasional treat in small amounts after frost or processing. Leaves and seeds contain amygdalin, which can hydrolyze to hydrogen cyanide and pose a poisoning risk. Feeding should be limited to fruit pulp only, excluding seeds and leaf material. Consult a veterinarian if signs of poisoning appear.

Open animal page

These guidelines are for general information only and do not replace veterinary diagnosis. If critical plant parts were ingested or the animal shows unusual behaviour or symptoms, seek veterinary advice.

Max risk

unknown

Highest status

do not feed

Urgency

contact a vet if symptoms appear

Practical tips

Blackthorn Practical tips

Common beginner mistakes

Attempting to harvest fruits before the first frost, leading to a very tart taste.Insufficient planting distance for hedges, resulting in uncontrolled, dense growth.

Success pattern

Planting in a sunny location with adequate space. Harvesting fruits after the first frost for optimal flavor development.Using it as a thorny hedge to protect beds or as a habitat for birds.

High-impact tips

Blackthorns require very little fertilizer and water. Once established, they grow almost on their own.Fruits can be easily frozen after harvest for later processing.

Grower observations

The blackthorn is a true survivor. It grows in the most unlikely places and still provides fruit every year if you just let it.While the thorns are a nuisance, they also make the blackthorn a perfect natural barrier against unwanted visitors in the garden.

Plant Profile

Additional plant images

Blackthorn (Prunus spinosa): whole plant for plant portrait - Wild plants, Rose family, Harvest October - December
Blackthorn (Prunus spinosa): whole plant for plant portrait - Wild plants, Rose family, Harvest October - December

Health

Pests, Diseases

Plant health

PestsDiseasesDeficiencies

Diagnosis help

Blackthorn Diagnosis help

Pest groups

AphidsSpinnmilben

Disease groups

MoniliaEchter Mehltau

Prevention

Choose a sunny location with good air circulation.Avoid waterlogging.Remove infested plant parts promptly.Encourage beneficial insects by planting flower strips.Regular pruning to improve ventilation.

Diagnosis

Look for yellow leaves, sticky deposits (honeydew) with aphids, or gray coating with mildew. Fruit rot appears as brown, shriveled fruits.

Cultural prevention

Regular pruning to improve ventilation and light penetration.Remove fallen fruit and infected plant parts.Standortwahl mit guter Luftzirkulation.Avoid mechanical injuries to fruits and bark.

Monitoring

Regularly check fruits for signs of rot.Watch leaves and shoots for powdery coating.Check for aphid infestation, especially on young shoots.

First response

At the first signs of powdery mildew: spray with diluted milk or horsetail extract.For Monilia: remove and destroy infected fruits and branches.For aphids: rinse with a water jet or use neem oil.

Diagnostic rules

Brown, mummified fruits that remain on the branch.

Possible causes: Monilia fructigena

  • Are the fruits damaged?
  • Was the weather humid during flowering?

White, powdery coating on leaves and young shoots.

Possible causes: Podosphaera pannosa (Echter Mehltau)

  • Is air circulation within the stand good?
  • Are the shoots young and actively growing?

FAQ

When is the best time to harvest sloes?

The best harvest time for sloes is after the first frost in late autumn (October to December). Frost makes the fruits milder and sweeter in taste.

Can sloes be eaten raw?

Raw sloes are hardly palatable due to their very tart and astringent taste. After the first frost or after processing (e.g., cooking, freezing), they become milder and can then also be consumed raw in small quantities.

How do I care for a blackthorn hedge?

Blackthorn hedges are very low-maintenance. An annual prune in late winter or early spring (March) for shaping and thinning is sufficient. Remove dead or crossing branches. Ensure the hedge remains well-ventilated.

Are blackthorns poisonous?

The fruits of the blackthorn are safe after processing or frost. However, the seeds (kernels) contain amygdalin, which can be converted to hydrocyanic acid in the body and therefore should not be consumed.

Is Blackthorn safe for Dog?

Blackthorn is classified as moderation only for Dog. Risk: unknown. Urgency: usually no action needed. Fruits are suitable in small amounts for dogs as a treat after frost or processing. Leaves and seeds should be avoided as they contain amygdalin, which can be converted to hydrocyanic acid. No direct species-specific poisoning cases are known in dogs, but caution is advised.

Is Blackthorn safe for Cat?

Blackthorn is classified as do not feed for Cat. Risk: unknown. Urgency: contact a vet if symptoms appear. The fruits of blackthorn can be given in small amounts as a treat, but leaves and seeds are toxic due to amygdalin (cyanide precursor) and should be avoided. If toxic parts are ingested, monitor for symptoms and seek veterinary advice if symptoms occur.

Is Blackthorn safe for Rabbit?

Blackthorn is classified as do not feed for Rabbit. Risk: unknown. Urgency: contact a vet if symptoms appear. The fruit of blackthorn can be fed in small amounts as a treat, but leaves and seeds are toxic due to amygdalin (cyanide precursor) and should be avoided. If toxic parts are ingested, monitor for symptoms and contact a veterinarian if symptoms occur.

Is Blackthorn safe for Guinea pig?

Blackthorn is classified as do not feed for Guinea pig. Risk: unknown. Urgency: usually no action needed. No reliable species-specific assessment is available. Fruits might be considered in very small amounts as a treat after frost or processing, but leaves and seeds should be avoided due to amygdalin.

Guides

Related guides

Garden guides

Sources

Public sources

  1. Wikidata entity

    Wikidata · 2026-05-15

  2. GBIF species match

    GBIF · 2026-05-15

  3. Deutschsprachige Wikipedia: Schlehdorn

    Wikipedia · 2026-05-15

  4. English Wikipedia: Prunus spinosa

    Wikipedia · 2026-05-15

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