European black nightshade (Solanum nigrum) or locally just 'black nightshade', duscle, garden nightshade, garden huckleberry, hound's berry, petty morel, wonder berry, small-fruited black nightshade, or popolo) is a species in the Solanum genus, native to Eurasia and introduced in the Americas, Australasia, and South Africa. Parts of this plant can be toxic to livestock and humans. Nonetheless, ripe berries and cooked leaves of edible strains are used as food in some locales, and plant parts are used as a traditional medicine. A tendency exists in literature to incorrectly refer to many of the other "black nightshade" species as "Solanum nigrum".
Solanum nigrum has been recorded from deposits of the Palaeolithic and Mesolithic era of ancient Britain and it is suggested by the botanist and ecologist Edward Salisbury that it was part of the native flora there before Neolithic agriculture emerged. The species was mentioned by Pliny the Elder in the first century AD and by the great herbalists, including Dioscorides. In 1753, Carl Linnaeus described six varieties of Solanum nigrum in 'Species Plantarum'.
Black nightshade is a common herb or short-lived perennial shrub, found in many wooded areas, as well as disturbed habitats. It reaches a height of 30 to 120 cm, leaves 4.0 to 7.5 cm long and 2 to 5 cm wide; ovate to heart-shaped, with wavy or large-toothed edges; both surfaces hairy or hairless; petiole 1 to 3 cm long with a winged upper portion. The flowers have petals greenish to whitish, recurved when aged and surround prominent bright yellow anthers. The berry is mostly 6 to 8 mm in diam., dull black or purple-black. In India, another strain is found with berries that turn red when ripe. Sometimes S. nigrum is confused for the more toxic deadly nightshade, Atropa belladonna, which is in a different Solanaceae genus altogether. A comparison of the fruit shows that the black nightshade berries grow in bunches, the deadly nightshade berries grow individually.
Solanine levels in S. nigrum can be toxic. Children have died from poisoning after eating unripe berries. However, the plant is rarely fatal, with ripe berries causing symptoms of mild abdominal pains, vomiting, and diarrhoea. Poisoning symptoms are typically delayed for 6 to 12 hours after ingestion. Initial symptoms of toxicity include fever, sweating, vomiting, abdominal pain, diarrhoea, confusion, and drowsiness. Death from ingesting large amounts of the plant results from cardiac arrhythmias and respiratory failure. Livestock have also been poisoned from nitrate toxicity by grazing the leaves of S. nigrum. All kinds of animals can be poisoned after ingesting nightshade, including cattle, sheep, poultry, and swine.
Nevertheless, S. nigrum has been widely used as a food since early times, and the fruit was recorded as a famine food in 15th-century China. Despite toxicity issues with some forms, the ripe berries and boiled leaves of edible strains are eaten. The thoroughly boiled leaves (although strong and slightly bitter flavoured) are used like spinach as horta (see here) and in fataya pies and quiches. The ripe black berries are described as sweet and salty, with hints of liquorice and melon. In South India, the leaves and berries are routinely consumed as food after cooking with tamarind, onion, and cumin seeds.
If you decide to pick and consume black nightshade, ensure you know that you are picking the right plant and also that you are preparing it correctly!
The plant has a long history of medicinal usage, dating back to ancient Greece. In the fourteenth century, the plant under the name of Petty Morel was being used for "canker" and with Horehound and wine taken for "dropsy". It was a traditional European medicine used as a strong sudorific, analgesic and sedative with powerful narcotic properties, but was considered a "somewhat dangerous remedy". Internal use has fallen out of favour in Western herbalism due to its variable chemistry and toxicity, but it is used topically as a treatment for herpes zoster. In the language of flowers, a sprig of flowering black nightshade signifies "truth".