BARBERRY (Berberis vulgaris)
A hedgerow shrub, scarce now in Britain, for most of it has been eradicated by farmers owing to the belief that its proximity to wheat caused fungus rust, though the fungus on barberry leaves is entirely different from wheat rust. The belief, though, seems to underlie the story quoted by Bottrell, from an old Cornish droll, which speaks of a farmer cutting down and uprooting all barberries around his property, in an attempt to break a spell. Or has the plant a connection with witchcraft?
According to Culpeper, the ley of barberry ash and water as a hair wash will turn it yellow, a use also reorded by Langham. From this, it was a small step to believing that it actually made the hair grow. You had to wash the head with the water in which barberry had been boiled — but “take care that the wash does not touch any part where the hair should not grow”. “To cause the hair to grow, take the barberry, and fill an iron pot therewith, fill it up with as much water as it will contain, then boil on a slow fire to the half. With this water, wash your head morning and evening” (Physicians of Myddfai).
The doctrine of signatures shows in a remedy for jaundice. The bark is yellow, and a decoction taken in ale or white wine was often used for the condition. Irish folk medicine recommended the bark in stout, with sulphur, the whole cooked together. Another Irish remedy involved brewing the root bark to a strong decoction that had to be taken every morning, fasting, for nine successive mornings. In Lincolnshire, a tea was made from the twigs and bark for gallstones and jaundice, and gypsies use a weak infusion of the berries for kidney trouble.