Lemon trees are grown primarily for their yellow, acidic fruits. Lemon fruits are often turned into juice, but pulp and zest are also utilized and can for instance be used in lemon pie and chutney. Lemon juice can also be used as a form of preservative. Approximately 5 percent of the lemon juice is made up by citric acid and lemons therefore have a very low pH value; typically from pH 2 to pH 3. Many schools use lemon juice for chemical experiments since lemon juice is a cheap, readily available and comparatively harmless acid.

Some Lemon trees exceed 20 feet (6 metres) in height, but it is more common for a Lemon tree to stay smaller than this. Lemon tree branches are thorny and create an open crown. The leaves are elliptical to acuminate, which means that they are oval with either a short point or en elongated point. The leaves are green and look shiny. The flowers of a lemon tree have a white exterior, while the interior is decorated with light purple streaks. The famous fruits display a bright yellow colouration. Unlike many other tree species, you can find flowers together with ripe fruits on a Lemon tree.

As mentioned above, the Lemon tree is a cultivar that has been created from wild citron species, most likely the wild citron and the wild mandarin. Exactly when and where the first lemons were formed as still unknown, but early mentions of lemon trees come from the Mediterranean region. Scientists do however suspect that the first lemon trees were grown in the Deccan Plateau, a hot and semi-arid part of central India. The name lemon is probably derived from the Sanskrit word “nimbuka”, via the Persian word “Limu”.

In Roman mosaics of North Africa, descriptions of citrus trees are present, and this have lead scientists to suspect that the citron was the first citrus fruit known to the Romans. The citron is also mentioned by Pliny the Elder (Gaius Plinius Secundus) in his Natural History XII, vii.15. Pliny the Elder was a Natural philosopher who lived from 23 to 79 A.D. He called the citron malum medicum due to its medical properties. Lemons have also been found in the ruins of Pompeii, a Roman city destroyed by a volcanic eruption in the year 79 A.D. The first unambiguous written description of a lemon, not a citron, can be found in an early Arabic treatise on farming from the 10th century. This treatise was written by Qustus al-Rumi. During late 12th century, Ibn Jami’, a physician who worked for the Muslim leader Saladin, wrote the first treatise focusing solely on the lemon tree.