Blackthorn (Prunus spinosa)

Blackthorn (Prunus spinosa)

  • Kingdom Plantae
  • Phylum Anthophyta
  • Class Magnoliopsida
  • Order Rosales
  • Family Rosaceae
  • Genus Prunus

Widespread in Britain southwards of Sutherland and Caithness and reaching altitudes of up to 415m in Yorkshire. Elsewhere, this shrub is found in Europe with the exceptions of the far north and north-east, and extends as far east as Iran. It also occurs in south-western Siberia. Blackthorn is related to the plums.

With a shrub height of 1-4m, its typical habitats include hedgerows, woodlands, scrub, cliff slopes and screes. On shingle beaches a prostrate form of blackthorn may occur. This shrub can tolerate a wide range of soil types. It doesn’t like heavy shade, but will provide protection for smaller plants growing underneath, and withstands strong winds. As it doesn’t mind wet either it is a good plant for coastal areas. Will thrive on quite poor soil but doesn’t like chalk. Blackthorn sends up many suckers which can be controlled by mowing, unless you particularly want a dense thicket. This is a very adaptable plant which will grow almost anywhere. Blackthorn is a large, sprawling, deciduous shrub that suckers readily and produces a very effective spiny hedge. It has traditionally been used with hawthorn as the main components of a mixed hedgerow.

The bark is black with long, quite vicious spines and the small leaves are serrated and dull green in colour and measure from 2 to 4 cm in length. The leaves provide food for the larvae of Black and Brown Hairstreak butterflies. The tree is also the food plant for the caterpillars of the following moths – March, Common Emerald, Little Emerald, Mottle Pug, Feathered Thorn, Orange, Scalloped Hazel, Scalloped Oak, Swallowtailed, Brimstone, August Thorn, Early Thorn, Pale Brindled Beauty, Blue Bordered Carpet, Broken Barred Carpet, November, Pale November, Winter, Sloe Pug, Green Pug, Sharp Angled Peacock and The Magpie. In fact, Blackthorn supports around 153 species of wildlife.

Blackthorn is very valuable to birds as a nesting site. Blackbird, song thrush, finches, common whitethroat and wood pigeon are among the more common users.

The beautiful white blossom tends to appear early in the year before the leaves. The single, white flowers are among the first to be seen in hedgerows from late February to early March and their appearance often seems to coincide with a period of bad weather, the so-called ‘blackthorn winter’.

These ‘heralds of spring’ attract early insects to pollinate them. The flowers are pollinated by a range of insects. The flowers produce nectar for bumblebees and early-flying Small Tortoiseshell butterflies.

The bitter fruits it produces are round blue-black berries known as sloes, and are used to make sloe gin and a damson-like (but incredibly bitter!) flavour. They are bluish-black in colour and often have a whitish powdery bloom. The flesh is green and there is a single stone inside. Fruit diameter: 10-15 mmIn addition to flavouring gin, sloes are used in jellies, conserves and syrups and were made to make sloe wine, an alternative to port. They have also been put to various uses in folk-medicine. The flowers are edible and the leaves have been dried and used as a substitute for tea. Furthermore, dyes have been obtained form the fruits, leaves and bark. The wood of blackthorn is extremely hard and is highly valued for making walking sticks as it shows interesting patterns and knot-holes.

The sharp thorns have been used for centuries as awls. Blackthorn is also the traditional wood used in wands for tribal medicine people and wise women etc. It is also used to make the traditional Irish shillelagh – cudgel – used in sports. The tree also makes good firewood, marquetry and walking sticks.

The dried juice of the berries makes gum acacia. The flowers and fruit make a good tonic for diarrhoea and other bowel problems. Sloe syrup has anti-rheumatic properties and can help fight flu. The plant is also good for nosebleeds, constipation and eye pain. Sloe berries were first used by herbalists for treating stomach problems and blood disorders. They are still used in wine, gin and vodka as flavouring. Sloes can also be made into a paste for whitening teeth and removing tartar. The berries taste better and not so bitter if harvested after a few frosts. Ancient folk used to bury the sloes in straw-lined pits for a few months to ripen them and make them sweeter. A Neolithic lake village in Glastonbury was found to have such a pit, full of sloe stones.

This thorny native plant has much folklore surrounding it. Also known as Snag.It was believed that Christ’s Crown of Thorns was made from Blackthorn. To bring Blackthorn blossom into the home meant a certain death would follow. In Herefordshire and Worcestershire, a wreath or globe of Blackthorn twigs would be scorched on a fire on New Year’s morning and then burned in a wheatfield in the furrows and its ashes scattered over the wheat. Then a new globe or wreath would be made and hung in the farmhouse kitchen ready for next year. It was believed that this ritual would rid the field of the devil. In a similar vein, Blackthorn would be scorched and hung up with mistletoe for good luck.Blackthorn in bloom is considered an emblem of life and death together as the flowers appear when the tree has no leaves, just black bark and thorns. It is considered wise not to grow three trees closely together. It is said that a Hawthorn will destroy any Blackthorn near it. On the Isle of Man it is believed that if the Blackthorn and the Hawthorn have many berries then the ensuing winter will be severe.

In Irish folklore it was believed that the “little people” lived in Blackthorn bushes. Fairy tribes, called Lunantishees, are said to guard Blackthorn trees and will not let you cut branches off it on 11 November or 11 May – if you do you will be cursed with bad luck. It was also bad luck to wear the flowers in your buttonhole. Another belief was that a Blackthorn wand with thorns fixed to the ends was harmful; while a carved rod carried by Devonshire witches was thought to cause miscarriage.

Feeding and other inter-species relationships Associated with Prunus spinosa:

Food plant ofis foodplant of Phyllobius oblongus – Brown Leaf Weevil (Coleoptera: Curculionidae) Morris, M.G., 1997is foodplant of larva Pristiphora monogyniae – a sawfly (Hymenoptera: Tenthredinidae) Benson, R.B., 1958
Associate ofis associate of Anthonomus rufus – a weevil (Coleoptera: Curculionidae) Bullock, J.A., 1992
Flowerflower is visited by imago Hoplocampa chrysorrhoea – a sawfly (Hymenoptera: Tenthredinidae) Benson, R.B., 1958flower is visited by imago Hoplocampa flava – a sawfly (Hymenoptera: Tenthredinidae) Benson, R.B., 1958flower is visited by imago Hoplocampa rutilicornis – a sawfly (Hymenoptera: Tenthredinidae) Benson, R.B., 1958
Fruitdeveloping fruit may contain larva Hoplocampa chrysorrhoea – a sawfly (Hymenoptera: Tenthredinidae) Benson, R.B., 1958 [generally falls off when larva is mature]developing fruit may contain larva Hoplocampa flava – a sawfly (Hymenoptera: Tenthredinidae) Benson, R.B., 1958 [generally falls off when larva is mature]developing fruit may contain larva Hoplocampa rutilicornis – a sawfly (Hymenoptera: Tenthredinidae) Benson, R.B., 1958 [generally falls off when larva is mature]fruit kernel may contain larva Rhynchites auratus – a leafroller weevil (Coleoptera: Attelabidae) Morris, M.G., 1990fruit may contain larva Rhynchites aequatus – Apple Fruit Rhynchites (Coleoptera: Attelabidae) Morris, M.G., 1990
Leafleaf (midrib) may contain larva Rhynchites pauxillus – a leafroller weevil (Coleoptera: Attelabidae) Morris, M.G., 1990 Bullock, J.A., 1992leaf (petiole) may contain larva Rhynchites pauxillus – a leafroller weevil (Coleoptera: Attelabidae) Morris, M.G., 1990 Bullock, J.A., 1992leaf is galled by Eriophyes similis – a gall mite (Eriophyidae) Stubbs, F.B. (Editor), 1986leaf is galled by larva Pristiphora monogyniae – a sawfly (Hymenoptera: Tenthredinidae) Stubbs, F.B. (Editor), 1986leaf is grazed by social larva Nematus lucidus – a sawfly (Hymenoptera: Tenthredinidae) Benson, R.B., 1958leaf is grazed by larva Pareophora pruni – a sawfly (Hymenoptera: Tenthredinidae) Benson, R.B., 1952leaf is grazed by solitary larva Pristiphora biscalis – a sawfly (Hymenoptera: Tenthredinidae) Benson, R.B., 1958
Ovaryovary may house ovum Hoplocampa chrysorrhoea – a sawfly (Hymenoptera: Tenthredinidae) Benson, R.B., 1958ovary may house ovum Hoplocampa flava – a sawfly (Hymenoptera: Tenthredinidae) Benson, R.B., 1958ovary may house ovum Hoplocampa rutilicornis – a sawfly (Hymenoptera: Tenthredinidae) Benson, R.B., 1958
Dead Wooddecaying shoot may contain larva Rhynchites caeruleus – Apple Twig Cutter, Twig Cutting Weevil (Coleoptera: Attelabidae) Morris, M.G., 1990
Prunus species are used as food plants by the larvae of a large number of Lepidoptera species including:
Monophagous species which feed exclusively on PrunusBucculatrix copeuta – feeds on Prunus pensylvanicaColeophora case-bearers:C. adjectella – feeds on P. spinosaC. amygdalinaC. demissella – feeds on P. virginianaC. lapidicornisC. prunifoliae – feeds on P. spinosaC. umbratica
Polyphagous species which feed on Prunus among other plantsAngle Shades (Phlogophora meticulosa)Autumnal Moth (Epirrita autumnata)The Brick (Agrochola circellaris) – recorded on Bird CherryBrimstone Moth (Opisthograptis luteolata)Brown-tail (Euproctis chrysorrhoea)Bucculatrix pomifoliellaBuff-tip (Phalera bucephala)Coleophora case-bearers:C. anatipennellaC. atlanticaC. atromarginataC. badiipennellaC. cerasivorellaC. coracipennellaC. hemerobiellaC. laticornella – recorded on P. americanaC. lineapulvellaC. malivorellaC. nigricellaC. palliatellaC. paripennellaC. pruniellaC. sacramentaC. spinellaCommon Emerald (Hemithea aestivaria)Common Marbled Carpet (Chloroclysta truncata) – recorded on Bird CherryCommon Quaker (Orthosia cerasi)Coxcomb Prominent (Ptilodon capucina) – recorded on Bird CherryDark Dagger (Acronicta tridens)Dot Moth (Melanchra persicariae) – recorded on Bird CherryDotted Border (Agriopis marginaria)Double Square-spot (Xestia triangulum) – recorded on BlackthornThe Dun-bar (Cosmia trapezina)Emperor Moth (Pavonia pavonia)The Engrailed (Ectropis crepuscularia)Feathered Thorn (Colotois pennaria)The Gothic (Naenia typica)Green Pug (Chloroclystis rectangulata)Grey Dagger (Acronicta psi)Hebrew Character (Orthosia gothica)Hypercompe indecisaIO moth (Automeris io)Lesser Broad-bordered Yellow Underwing (Noctua janthina) – recorded on BlackthornLesser Yellow Underwing (Noctua comes) – recorded on BlackthornLight brown apple moth (Epiphyas postvittana)Light Emerald (Campaea margaritata)Lime Hawk-moth (Mimas tiliae)Mottled Pug (Eupithecia exiguata)Mottled Umber (Erannis defoliaria)Mouse Moth (Amphipyra tragopoginis)November Moth (Epirrita dilutata)Pale November Moth (Epirrita christyi)Purple Thorn (Selenia tetralunaria)The Satellite (Eupsilia transversa)Scalloped Hazel (Odontopera bidentata) – recorded on Bird CherryScalloped Oak (Crocallis elinguaria) – recorded on Bird CherryShort-cloaked Moth (Nola cucullatella)Willow Beauty (Peribatodes rhomboidaria)Winter Moth (Operophtera brumata)Yellow-tail (Euproctis similis)

Species composition of hedgerows and verges have an infinite variety where not only are no 2 the same, but they are different every 100 yards or sometimes every few yards.