In fact the region where the citrus fruit originated lies, most likely, between the south-eastern edge of the Himalayas, Assam, and the north of Burma. From there, it spread towards India, China, particularly Yunnan region, the Indo-Chinese peninsula and towards Japan and the Malaysian archipelago.
The first citrus fruit that appeared in the Mediterranean region was the citron Citrus medica. It has lemon like fruits with a nipple-like end. The citron spread from Persia to Palestine and in 136BC the Jews replaced the cedar cone as an offering at the Feast of Tabernacles with a citron. From that we can conclude that the citron fruit was already in cultivation in Palestine. The Jewish population around the Mediterranean basin were largely responsible for the spread of this fruit as it was necessary element in their religious rituals.
Between 8th–10th century the Arabs introduced the bitter Seville orange Citrus aurantium and the lemon tree Citrus limon from Mesopotamia (present day Iraq) to Syria. From there, the cultivation of these trees spread through the countries along the Mediterranean sea as far as Spain, Sicily and Morocco. The lemon tree was introduced in Tuscany around 1260, and on the Ligurian coast at the end of the 14th century, the lime Citrus aurantiifolia was introduced into Sicily by the 13th century.
The sweet orange Citrus sinensis, the most used citrus fruit today, came rather late on the scene, after the lemon and the lime. In the 15th century sweet oranges were producing fruit in Liguria.
The grapefruit Citrus maxima was originally introduced to Europe in the 13th century as an ornamental curiosity.
The mandarin Citrus reticulata or tangerine Citrus deliciosa has been cultivated in the Mediterranean region since 1805.
An essence is extracted from the rind of the bergamot Citrus bergamia, a hybrid of the bitter Seville orange and the lemon, and is used as an important element in Eau de Cologne and of course Earl Grey tea.
All these trees are for sale at Pépinière Bachès, mentioned by Elisabeth.
Looking through them all I found that the hardiest of them, with the most likelihood of success are:
The mandarin (satsuma) trees - Citrus unshiu Clausellina, C unshiu Hashimoto, C unshiu Okitsu, C unshiu Owari, C unshiu Saigon can cope with temperatures between -10°C and -12°C.
The Kumquats - Fortunella hindsii, F japonica, F kugli and F margarita can cope with temperatures between -10°C and -12°C.
But you never know, Michèle’s tree is an exception to the rule, normally the grapefruit Citrus maxima can cope up to -6°C. In our region it is very often much colder then that.
The same goes for the magnificent lemon tree in the centre of Lorgues. It seems the more sheltered the spot is the more chance of success.
I think they are definitely worth a try !