It is thought that the lemon originates from Southeast Asia. However, the Romans were cultivating it in Italy in the first century AD, as during excavations of Pompeii a fresco was found which depicts what looks very much like a lemon tree. Lemon cultivation initially was spread by the Arabs, into the Mediterranean, where cultivation continues today. In the late-fifteenth century, lemons arrived in the New World and today, lemon production continues to be economically important in countries such as Argentina and Mexico.
Lemons are particularly high in vitamin C and so have been used to cure and prevent scurvy, which was a problem, particularly amongst sailors, where supplies of fresh fruit and vegetables were in short supply. The cause of scurvy has been known since at least the fifteenth century, but it seems that this knowledge slipped in and out of use over the last 500 years. It was not until the late-eighteenth century that citrus juice was introduced as part of a sailor's diet. Today lemons are widely used in foods, polish, non-toxic pesticides, cosmetics and traditional medicine.
From the seventeenth century, orangeries became a popular feature in gardens of those wealthy people who wished to grow the latest fashionable garden plants such as citrus. The buildings were south facing with large windows, often with glass in the roof and were heated by fires or stoves, although the fumes from these often killed the plants.
Lemon trees can grow to over six metres tall, they have dark green, leathery leaves and produce, mainly in winter, beautifully-scented white flowers, backed with purple. The yellow, pointed fruits take four to twelve months to ripen and are usually harvested from late summer into winter.
Lemons have been growing in the Oxford Botanic Garden since at least 1676. A container-grown Citrus limon 'Lunario' currently grows in the Garden, together with other citrus plants. From late May, after the frosts, the citrus plants are moved to a bright spot out in the garden for the summer. They remain there, regularly watered and fed, during the summer until September, when they are moved back into the bright and airy Conservatory for the winter months. A lemon tree can tolerate temperatures to a few degrees above freezing if kept on the dry side, but is happier with a minimum of around 7-10 degrees Celsius. Pests such as scale insect and aphid can be a problem.
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Harris SA 2015. What have plants ever done for us? Bodleian Library.