When should I harvest the fruit?

Harvest after the first frost, which helps reduce the astringency of the berries.

Can I grow this in a small garden?

It is best suited for larger spaces or as a boundary hedge due to its suckering habit.

Plant guide

Blackthorn.

Prunus spinosa

Pronounced PROO-nus spy-NO-suh

Also known as Blackthorn

The blackthorn is a hardy, deciduous shrub known for its dense, thorny branches and early spring blossoms. It produces small, dark blue fruits called sloes that are perfect for making jams or liqueurs. You will often see it forming thick, protective hedges in the wild.

Another photo of Blackthorn — Photo by Daniel Linzbauer (CC BY) via gbif

At a glance

Care level: Easy
Plant type: Deciduous shrub
Light: Full sun
Indoor light: Direct sun
Water: Every 7 to 14 days
Mature size: 10 to 15 feet
Growth rate: Medium
Hardiness: USDA 4 to 8
Bloom time: Early to mid spring

Care

Plant this shrub in a sunny spot with well-draining soil to encourage the best fruit production. Keep an eye out for aphids or blackthorn sawfly during the growing season. Pruning helps keep the dense, thorny growth manageable and tidy.

Watering: Water regularly during the first year until the root system is established.
Feeding: Apply a balanced organic fertilizer in early spring to support new growth.
Pruning: Prune in late winter or early spring to remove dead wood and shape the shrub.
Repotting: Repot only if growing in a container, moving to a slightly larger pot every few years.
Soil: Loamy, chalky, or clay soils
Soil pH: Neutral to alkaline
Temperature: -30 to 35°C
Humidity: 40 to 70%
Drought tolerance: Moderate
Lifespan: Perennial, typically 30 to 50 years
Fragrance: Light
Deer and rabbits: High

Signs it needs repotting

Roots growing out of drainage holes
Stunted growth despite proper care

Safety

People: The seeds are toxic if ingested in large quantities due to hydrogen cyanide content.
Pets: The foliage and seeds contain cyanogenic glycosides which can be toxic to cats and dogs if ingested.
Children: The dense, thorny branches pose a significant scratching hazard to small children.
Contact allergens: The sharp thorns can cause mechanical skin irritation and minor puncture wounds.
Airborne allergens: The pollen may cause mild seasonal allergic reactions in sensitive individuals.
Edibility: The seeds contain cyanogenic glycosides and should not be consumed.

How to identify it

Dense, spiny, dark-colored branches
Small, white, five-petaled flowers
Oval, serrated, dark green leaves
Small, round, blue-black drupe fruits

Height: 2 to 4m
Spread: 2 to 4m
Leaves: green, deciduous
Flowers: white, 1 to 2cm
Fruit: blue, black, Late autumn

Problems to watch for

AphidsCommon
Black KnotCommon
CaterpillarsUncommon
Plum CurculioUncommon
Powdery MildewUncommon
Scale InsectsUncommon
Shot Hole DiseaseUncommon
CankerRare

By symptom

Plant problems by symptom

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Growing it

Propagation: seed, suckers, cuttings
When to plant: spring, autumn
Overwintering: No special protection is needed as it is fully hardy. Simply clear away any fallen debris to prevent fungal buildup.
In containers: Not recommended for containers due to its vigorous suckering habit and large size.

Suckers

1. Identify a healthy sucker growing away from the main plant.
2. Carefully dig down to find the root connection.
3. Sever the root with a sharp, clean spade.
4. Lift the sucker with as much root as possible.
5. Replant immediately in a prepared site.

Plant in a sunny, open location to ensure dense growth and better fruit production.

Grows well with

Hawthorn · They share similar growing requirements and form excellent mixed native hedges.
Dog rose · This climber thrives when supported by the sturdy, thorny structure of the blackthorn.

Similar species

Cherry plum · It blooms earlier and lacks the intense thorniness of the blackthorn.

Science

Family: Rosaceae
Genus: Prunus
Order: Rosales
Class: Magnoliopsida
Native range: Europe, Western Asia, and parts of North Africa.
Conservation: This species is common and not of conservation concern.

It thrives in scrubland and hedgerows, where its thorny thickets provide essential protection for nesting birds.

Value to wildlife: larval host plant, nectar source, provides nesting cover
Pollinators: bees, butterflies, beetles
Uses: hedging, wildlife habitat, culinary, erosion control

Through the year

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Flowering

Fruiting

Foliage

Ecological indicators

Salinity: 2/9
Soil reaction: 6/9
Light: 7/9
Temperature: 5/9
Moisture: 5/9
Nutrients: 5/9

Taxonomy resolved against GBIF.

Questions people ask

When should I harvest the fruit?: Harvest after the first frost, which helps reduce the astringency of the berries.
Can I grow this in a small garden?: It is best suited for larger spaces or as a boundary hedge due to its suckering habit.

Where the name comes from

The name spinosa refers to the many sharp thorns found along its branches. It is commonly known as blackthorn due to its dark, almost black bark.

Good to know

It is often called blackthorn because of its dark, thorny bark.
The wood is extremely hard and was historically used for walking sticks.
It is a classic choice for traditional hedgerows in Europe.
The flowers appear before the leaves, creating a striking white display.

Also in

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This guide was generated with AI on September 26, 2026 and checked against GBIF taxonomy. It is general information, not horticultural or veterinary advice. Read about how we build these guides.