Lemon and other citrus trees are an iconic part of the Southern California landscape. They are ideally suited to growing in only a few mild-winter areas of the United States including Central to Southern California, Southern Florida, and Southern Texas. They are more sensitive to cold temperatures than other citrus. They can be grown in other areas, but usually with special care, with only limited species and varieties, or in containers for indoor growing during cold winters. As Aesop said, familiarity breeds contempt; lemon and other citrus being taken for granted in their California growing range is in contrast to gardeners in colder regions who sometimes go to great lengths to keep a small number of citrus trees alive, achieve fruit set under adverse conditions, and hopefully, once in a while, harvest a few homegrown, tree-ripened fruits.
Lemons are small trees in the Citrus genus and the family Rutaceae, the rue family, with many of its numerous plant members known for producing strongly aromatic, flavorful, or medicinal leaves and/or fruit. They have beautiful flowers with a purplish-red hue at the base. Lemons that are commonly grown in the home garden and landscape include Eureka, Lisbon, and Meyer (actually a cross between and lemon and orange) lemons. Sweet citrus in general, require heat to develop high sugar content in fruits; while lemons are often able to produce good-quality fruit in cooler climates, and are therefore widely adaptable.
The agricultural origins and exact native range of lemons remains unknown; it is believed that lemons originated in Southern China, Northeast India, and/or parts of Southeast Asia, and were introduced to Europe for the first time around the first century AD. Lemons became widely cultivated in Europe for the first time in the 15th century. Simultaneously, lemons were introduced to the Americas by Columbus.
Lemons have been used throughout history for seasoning food, drink, and for their medicinal, aromatic, cleansing, and preservative properties. Today, lemons are an important component of the California produce industry, especially in coastal areas, with around eighty percent of the lemon production in the United States from California. One of the most important production areas is Ventura County, as it provides a climate that can allow the Eureka lemon to bear nearly year-round. Lemon trees are now grown in Mediterranean, subtropical, semitropical, and tropical regions worldwide, and may one of the most cultivated fruit trees in the world.
Though lemon are known for their high vitamin C content, they are not as rich as oranges in vitamin C. They also contain dietary fiber, and small levels of carbohydrates, thiamin, folate, calcium, iron, and potassium. One medium-sized lemon can contain up to 50% of the USDA recommended daily vitamin C. However, this statistic is based on the analysis of a peeled raw lemon, and as one does not usually consume lemons whole, one generally has to consume more lemon than other fruits to achieve the same Vitamin C intake.