Garden sorrel (Rumex acetosa) and sheep's sorrel (Rumex ascetosella) are indigenous to Britain. Cultivated French sorrel (Rumex scutatus) tastes very similar though the leaves are a different shape. Wood sorrel is a completely different plant, though also a traditional herb used for soups and salads.
When the leaves are under 7.5cm long, they can be used raw in salads, especially with dandelion leaves. Bigger leaves can be made into soups, sauces and risotto. Khaki-coloured sorrel purée is a good acidic accompaniment to oily fish, chicken or veal, or poached eggs on toast. It can be stirred into crème fraîche to give quick sauce. Add a few leaves of watercress, spinach or parsley if you want a brighter green colour. Chop sorrel like a herb to add to stuffings and crumb coatings. The lemony taste means sorrel can also be added carefully to fruit salads, jellies, custard and fruit drinks, as lemon balm or verbena.