Here's a herb I know well as it grows in my garden back home in London and regularly feeds visitors. However, the diners are not humans... but the robins, blackbirds and pigeons who feast on the berries every year.
Ripe barberry fruits
North Africa or Western Asia.
Berberis vulgaris is, or European barberry, is a shrub native to Central and Southern Europe, North-Western Africa and Western Asia. The plant is now naturalised in Northern Europe, including Britain, Scandinavia and North America.
Fruits and seeds (each fruit contains 2 or 3 seeds). Other parts of the plant can cause a light, non-fatal poisoning.
Berberidaceae (barberry family).
Sour and pleasantly tart, with acidity approaching that of tamarind.
The common name "barberry" and botanical genus name berberis derive from the Middle English barbere, in turn derived from the Latin barbaris and from the Greek barbaroi "stammerers" (any foreigner who could not speak Greek was a barbaros who was said to utter nonsense such as "bar-bar"). The term is ultimately derived from an Indo-European root and appears in Sanskrit as barbaras "stammering".
The name was passed to Arabic as al-Barbar, originally any people whom the Moors encountered who could not speak Arabic (notably the Berber people, whose language has never been Arabic). In contemporary English we still refer to those of supposed uncultured origin as "barbarians".
The species name vulgaris is Latin for "common". The English name "holy thorn" has obvious biblical connotations and the French épine-vinette also refers to the sharp thorns.
Common barberry is a complex plant which is toxic but has both culinary and medicinal applications. In Europe, the berries are traditionally used for making jam. In South-Western Asia, especially Iran, the berries are used as a culinary spice, typically to lend flavour, aroma and colour to rice.
Barberry is a host for puccinia graminis "black rust", a disease of wheat. Wheat farmers had accused barberries of spreading rust as early as 1660, but were derided as superstitious by jam makers. The accusation was scientifically proven in 1865, since which date cultivation of European barberry has been prohibited in many areas because of the impact of the disease on wheat crops.
Barberry stem bark and root bark are used both as a homeopathic medicine and as a herbal medicine recommended (in modest quantities) to aid the secretion of bile, aid with liver problems, act as a purgative and help regulate the digestive processes. Taken in larger amounts, however, berberine causes a variety of unpleasant symptoms.