Black nightshade (or blackberry nightshade) Solanum nigrum is a highly adaptable plant, and a common weed across Australia, from the south to the tropical north. The species can look quite different from region to region. It produces small edible fruits throughout the year (depending on the region.) Black nightshade has often been confused with deadly nightshade Atropa belladonna: although the berries look similar, those of black nightshade bunch, while deadly nightshade has single berries along its branches. Deadly nightshade contains very toxic tropane alkaloids; it hasn’t naturalised in Australia.
As with many nightshades, eating too much of the unripened fruit can cause stomach upset. And as with nightshades (such as potatoes, eggplants, kangaroo apples and tomatoes), there have been questions about edibility by humans: tomatoes were considered toxic up until the 18th century. But despite all the concern, black nightshade produces forageable berries (when ripe) and leaves (when cooked) which have been, and are still, used in many parts of the world for a variety of culinary and medicinal purposes (although no longer for internal use in western medicine because of variable chemistry and toxicity).
Black nightshade is an erect annual, though in cooler climates behaves more like a perennial. The leaves are oval to eggshaped, have a pointed tip, often have hints of purple on the top, and can be toothed along the margins. The flowers are white with yellow tips, and petals that bend backwards. The small fruits have a texture like cherry tomatoes. The unusual flavour is mostly sweet, but with bitter and sour undertones. The juvenile plants look similar to eggplant seedlings. Blackberry nightshades sow themselves, are hardy, need no tending, feeding or watering and rate as an important food source in our household’s ‘climate-changing economies’.
The berries are excellent: when ripe, as a snack; in smoothies; made into jam or fruit leathers (if you have the patience to collect enough); served on yoghurt or ice cream; or sprinkled as a garnish over a salad. The berries have been used as a dye in preserved fruits, the leaves as a cooked vegetable, and the whole plant can be dried and used as a herb. In Chinese medicine this herb has been used to treat a number of complaints including ringworm, gout, earache, coughs, colds, diarrhoea and inflammations.
Black nightshade often grows in cracks in public places where dogs like to urinate and where herbicide may be applied, so be mindful where you collect it from. Your own garden or community garden, or parkland that is managed without the use of pesticides, are probably safer places to forage for these fruits.
Some sources state that this plant contains toxic alkaloids, and that the unripe berries have proven fatal to children, but this information may derive from those ideologically opposed to free and forageable weed species. Foragers and wild food teachers like me, who have eaten these plants for many years, have a different view. If you’re concerned, cooking will eliminate alkaloids, or just stick to the raw black (ripe) berries.