Delicate and hard to transport, mulberry fruit is hard to come by in shops, but London has a bountiful supply of mulberries to forage from. Black mulberries are generally considered far tastier than white mulberries, having a sweeter taste compared to the white's more acidic tang. Fortunately, the majority of mulberries found in London are of the black variety (Morus nigra), which are ripe in late July and August.
You may already know of a local mulberry but if not you can learn to identify a mulberry tree here, then take a look at our online map - look for the black mulberries in particular! You can normally collect the fruit for personal use but leave plenty for others to enjoy, including wildlife.
The fruit is notorious for staining - at Buckingham Palace, guests of summer parties are literally caught red-handed after sampling fruit of the garden's National Mulberry Collection! So wear gloves and an apron or old clothes when picking the fruit.
If you don't eat all the mulberries as you pick them, back home you can make delicious recipes inspired by the black mulberry's Persian and Middle Eastern provenance, and British staples with a mulberry twist. You can find some of these tasty dishes here. You can store the mulberries by placing them in a bowl of cold water (don't leave them under a running tap or the delicate berries could be pulverised!) before placing them in the fridge - they should keep for 2 - 3 days.