There are about 200 shrubby species of barberry distributed mainly throughout the northern hemisphere but with some also in southern and central America. Garden designer Bengt Schalin mentions in his book having successfully tried over 50 of them in his garden at Kirkkonummi, in southern Finland. He starts his description with the common barberry, which is “among the oldest of our garden shrubs.”
Common barberry is at its best when it flowers in June. Mimosa-yellow flowers hang in clusters from beautifully curving prickly branches. Pollination in these flowers is rather unusual: when insects seeking nectar touch the base of the stamen, it suddenly springs up and the pollen thrown out of the anther sticks to the insect’s head, from which it is transferred to the stigma of the next flower visited.
The red berries which ripen after flowering are nowadays just a visual attraction though earlier in Finland, as in many other countries, they were collected for their citric acid and vitamin-C. The seeds must be removed before use. The shrubs have also been used in folk medicine since ancient times.