Seasonal Wild Flowers

Blackthorn

Latin name

Prunus spinosa

Family

Rosaceae

Other names

Sloe

Flowering Season

March to May (after Cherry Plum).

English distribution

It is found throughout the country.

BSBI distribution map for Blackthorn

Habitat

Blackthorn grows in hedges, woods, open land, cliffs and

shingle beaches.

Description

Blackthorn is a native, deciduous, shrub with long, black

thorns, growing up to 4m.

The flowers appear before the leaves and are shining white

and up to 1.5cm across.

There are 20 stamens with long, white filaments and yellow

anthers.

The style is long, light green and with a capitate stigma.

The fruits (sloes) are drupes and are purplish with a blue

sheen.

They are not edible but are used to flovour sloe-gin.

The leaves are oval, slightly toothed and with a short

petiole.

The stems are rigid and much branched, and the twigs

turn dark brown to black after their first winter.

Short lateral shoots form the thorns.

It reproduces by seed and suckers, which can result in

anti-personnel thickets.

Blackthorn is highly invasive and will take over scrubland

and grassland, causing a problem in nature reserves.

It is susceptible to massive infestations by Brown-tail Moth

Caterpillars which completley strip the shrubs of leaves.

The caterpillars look attractive but the hairs can cause

skin irritation.

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Blackthorn blossom, South Somerset

Shrub in a hedge

Blossom at the end of a twig

5 petals, 20 stamens

Single green style, capitate stigma

Leaves and young fruits

Sloes and thorns

Sloes

Leaves

Short thorn

Long black thorns outlined against a white web

Brown-tail MothCaterpillar webs in May 2018.

The leaves have all been eaten.

Brown-tail Moth Caterpillars within their web

Brown-tail Moth Caterpillar on a warning notice

Warning notice, Durlston Country Park and

Nature Reserve, Swanage, Dorset