Rumex sanguineus =Sometimes known as wood dock, this is a handsome, compact version of sorrel (Rumex acetosa) growing to 30 cm, and it is a perennial, edible leafy green. It is a hardy and undemanding plant and makes an attractive clump of sword-shaped leaves, with red veins. The young leaves are preferable for eating than the older ones and are at their best from early spring to autumn. However, they are not as tasty as the usual sorrel and are more used as a decorative element in salads. Removing the unappealing flowering stalks in summer will increase leaf production in autumn. It prefers part shade, likes some moisture, and does best if divided and replanted every few years. Sorrel contains oxalic acid, to which some people are sensitive; it's best to avoid eating large quantities of it, or else cook it before consuming.