Sloe - Blackthorn

Prunus spinosa

Physical Characteristics

Prunus spinosa is a deciduous Shrub growing to 3 m (9ft 10in) at a medium rate. See above for USDA hardiness. It is hardy to UK zone 4. It is in flower from March to April, and the seeds ripen in October. The species is hermaphrodite (has both male and female organs) and is pollinated by Insects. The plant is self-fertile. It is noted for attracting wildlife. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils and prefers well-drained soil. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils and can grow in very alkaline soils. It can grow in semi-shade (light woodland) or no shade. It prefers moist soil. The plant can tolerate maritime exposure.

Distribution

Europe, including Britain, from Scandanavia south and east to the Mediterranean, Siberia and Iran.

Habitats

Woodland Garden Sunny Edge; Dappled Shade; Hedge;

Edible Uses

Edible Parts: Flowers Fruit Seed Edible Uses: Tea Fruit - raw or cooked[2, 5, 7, 11, 12, 13, 34]. Exceedingly astringent, it is normally cooked but once the fruit has been frosted it loses some of its astringency and some people find they can enjoy it raw[183, K]. The fruit is more usually used in jellies, syrups, conserves etc and as a flavouring for sloe gin and other liqueurs[183]. Some fruits that we ate in December were fairly pleasant raw[K]. In France the unripe fruit is pickled like an olive[183]. The fruit is about 15mm in diameter and contains one large seed[200]. Seed - raw or cooked. Do not eat the seed if it is too bitter - see the notes above on toxicity. The leaves are used as a tea substitute[7, 183]. The dried fruits can be added to herbal teas[183]. The flowers are edible and can be crystallised or sugared[183].

Medicinal Uses

Antidiarrhoeal Antiflatulent Antispasmodic Aperient Astringent Depurative Diaphoretic Diuretic Febrifuge Laxative Stomachic The flowers, bark, leaves and fruits are aperient, astringent, depurative, diaphoretic, diuretic, febrifuge, laxative and stomachic[7, 9, 21]. An infusion of the flowers is used in the treatment of diarrhoea (especially for children), bladder and kidney disorders, stomach weakness et[9]. Although no specific mention has been seen for this species, all members of the genus contain amygdalin and prunasin, substances which break down in water to form hydrocyanic acid (cyanide or prussic acid). In small amounts this exceedingly poisonous compound stimulates respiration, improves digestion and gives a sense of well-being[238]. The German Commission E Monographs, a therapeutic guide to herbal medicine, approve Prunus spinosa Sloe - Blackthorn for inflammation of mouth and pharynx (see [302] for critics of commission E).

Known Hazards

Although no specific mention has been seen for this species, it belongs to a genus where most, if not all members of the genus produce hydrogen cyanide, a poison that gives almonds their characteristic flavour. This toxin is found mainly in the leaves and seed and is readily detected by its bitter taste. It is usually present in too small a quantity to do any harm but any very bitter seed or fruit should not be eaten. In small quantities, hydrogen cyanide has been shown to stimulate respiration and improve digestion, it is also claimed to be of benefit in the treatment of cancer. In excess, however, it can cause respiratory failure and even death. Avoid excessive intake and use recommended doses.