I wondered if Kathy meant blackcurrants which have a blueish bloom, but had forgotten the name of them. Are there berries called blueberries then? Sloe also has a blueish bloom, it's the fruit of the blackthorn, aka Maytree, whence the country rhyme 'ne'er cast a clout til May be out' meaning, don't shed winter clothes until the blackthorn is in flower. if it was wild fruits she was gathering it would most likely be one of sloe, which you can use for a lot more than sloe gin, blackberries, elderberries,or haws, haw and blackcurrant jelly or cordial being a sovereign remedy for sore throats and coughs. Elderberry makes wine or cordial, which are also good for cold cures. Charlotte would know all the country nostrums with a quiverful of children, because she wouldn't be able to afford a doctor for minor ailments. Sloe however isn't commonly picked until it's had a frost on it [like frost-plums] or it's a bit astringent.