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Common Name: Sweet Orange

General Information

Citrus sinensis is an evergreen tree that can grow up to 9.00 metres tall.
It is harvested from the wild for local use as a food, medicine and source of materials.

Known Hazards

None known

Botanical References

Range

Original range is obscure, possible Asia in southern China and Vietnam.

Habitat

Original habitat is obscure, possibly an introgressed hybrid of C. maxima x C. reticulata[].

Properties

Edibility Rating
Medicinal Rating
Habit	Evergreen Tree
Height	9.00 m
Pollinators	Apomictic, Insects
Self-fertile	Yes
Cultivation Status	Wild

Cultivation Details

Prefers a moderately heavy loam with a generous amount of compost and sand added and a very sunny position[, ]. Prefers a pH between 5 and 6[]. Tolerates a pH in the range 4.3 to 8.3. Plants are intolerant of water logging[]. When growing plants in pots, a compost comprising equal quantities of loam and leafmould plus a little charcoal should produce good results[]. Do not use manure since Citrus species dislike it[]. When watering pot plants it is important to neither overwater or underwater since the plant will soon complain by turning yellow and dying. Water only when the compost is almost dry, but do not allow it to become completely dry[].
The sweet orange is widely grown for its edible fruit in warm temperate and tropical zones, there are many named varieties[]. In Britain it can be grown in a pot placed outdoors in the summer and brought into a greenhouse during the winter[]. Plants are almost hardy in the mildest areas of Britain[] but the fruit is insipid if it is developed when the mean temperature is below 18°c[]. The young growth in spring, even on mature plants, is frost-tender and so it is best to grow the plants in a position sheltered from the early morning sun[].
The flowers are sweetly scented[].
Plants dislike root disturbance and so should be placed into their permanent positions when young. If growing them in pots, great care must be exercised when potting them on into larger containers[].

Edible Uses

Fruit - raw. Sweet and delicious[, , , ]. The juice is often extracted from the fruit and sold as a refreshing and healthy drink or used in jellies, ice cream etc[].
The rind of the fruit is often used as a flavouring in cakes etc or made into marmalade[, , ].
Flowers - cooked as a vegetable or made into a tea[].

Medicinal

Citrus species contain a wide range of active ingredients and research is still underway in finding uses for them. They are rich in vitamin C, flavonoids, acids and volatile oils. They also contain coumarins such as bergapten which sensitizes the skin to sunlight. Bergapten is sometimes added to tanning preparations since it promotes pigmentation in the skin, though it can cause dermatitis or allergic responses in some people[]. Some of the plants more recent applications are as sources of anti-oxidants and chemical exfoliants in specialized cosmetics[].
The fruit is appetizer and blood purifier[]. It is used to allay thirst in people with fevers and also treats catarrh[].
The fruit juice is useful in the treatment of bilious affections and bilious diarrhoea[].
The fruit rind is carminative and tonic[]. The fresh rind is rubbed on the face as a cure for acne[].
The dried peel is used in the treatment of anorexia, colds, coughs etc[].

Other Uses

A semi-drying oil obtained from the seed is used in soap making[, ].
An essential oil from the peel is used as a food flavouring and also in perfumery and medicines[, , ].

Propagation

The seed is best sown in a greenhouse as soon as it ripe after thoroughly rinsing it[, ]. Sow stored seed in early spring in a greenhouse[]. Germination usually takes place within 2 - 3 weeks at 13°c. Seedlings are liable to damp off so they must be watered with care and kept well ventilated. The seed is usually polyembrionic, two or more seedlings arise from each seed and they are genetically identical to the parent but they do not usually carry any virus that might be present in the parent plant[]. When large enough to handle, prick the seedlings out into individual pots and grow them on in the greenhouse for at least three growing seasons before trying them outdoors. Plant them out in the summer and give them some protection from the cold for their first few winters outdoors.
Cuttings of half-ripe wood, mid summer in a frame.
Layering in early autumn.