Persian Berries or Avignon berries are amongst my favourite dyes and I usually have a pot on the go . They were extensively used in the Middle Ages, and yield a golden yellow veering towards bronze They are high in tannin which means they will dye cotton and other cellulose fibres well, but dye wool too. Add a rusty nail or two to the dye bath to achieve a lovely olive green
Persian berries are substantive (that is need no mordant) but you will get a better fix and depth of colour if fibres are premordanted with alum .
These berries come from Rhamnus cartharticus ,the purging buckthorn, a native to Britain and used extensively in hedging in England and a good source of food for the brimstone butterfly which will travel up to 20miles in search of it
I have just planted my first lot of purging buckthorn but it will be a while before they mature.