This lovely Scottish folk song names four of the most familiar cottage-garden herbs in its refrain. Curiously they were all taken to Britain by the Romans, who spread their favorite herbs throughout their empire. For thousands of years, aromatic rosemary (Rosmarinus officinalis) has figured in cooking, medicine and folklore. The Ancient Greeks would wind garlands of rosemary around their heads to quicken the memory, and early Christians believed that the Virgin Mary spread her pale-blue cloak to dry on a rosemary bush, which miraculously tinted the flowers blue. The plant is a slow-growing, evergreen shrub that can reach 2 meters in height. It flowers both in spring and autumn. As a native of the sunny Mediterranean, its small, leathery leaves are designed to retain moisture. The plant's aromatic oil is stored on the pale underside of the leaves, and as it evaporates it also helps to reduce water loss. Simply brushing against the leaves will produce a cloud of fragrance, and this deters animals from eating the plant. Essential oil of rosemary is highly valued in aromatherapy, as it can improve blood circulation and also lift the spirits.