Are the fruits of Mahonia x media ‘Charity’ edible, similar to Mahonia x media?
First, an aside: Mahonia has been ‘moved’ to Berberis, so that now Mahonia x media is named Berberis x hortensis, and Mahonia aquifolium is now Berberis aquifolium. Since the resources I will be quoting use the former names, I will leave them as they are.
Here’s what British author Alys Fowler says in her book, The Thrifty Forager (Kyle Books, 2011):
“All Mahonia species are edible, long-used for jams and juices in their native homes […] Sometimes you’ll find Mahonia nervosa, the Oregon grape, with the roundest grape-like berries. It looks very like Mahonia aquifolium but usually fruits later, around early autumn. […] Even when fully ripe, the acidic berries [of all Mahonia species] are too bitter to eat raw–they should be cooked into pies, jellies and jams. The flowers are edible, but bitter. The fruit needs to be picked and processed into jam or jelly very quickly, and it stains everything. It’s very low in pectin, so either add crab apples or add liquid pectin, following the usual jam making rules. You can also make an Oregon grape cordial which tastes a bit like blackcurrant cordial. Because of the low sugar content, it will need to be frozen if you want to store it–it’s a very sharp cordial, I use 350-400g (just under 1 lb) if granulated sugar to 600 ml (1 pint) of fruit. If that’s still too sharp, try mixing it with concentrated apple juice to sweeten it.”
Plants for a Future Database has pages for several Mahonia and Berberis species, including Mahonia x media, and its fruit is listed as edible.