Sour orange (Citrus aurantium)
Other names bitter-orange, king-orange, seville-orange, sour-orange
At a glance
- Lifecycle
- Perennial (hardy)
- Exposure
- Full sun
- Time to harvest
- 140–330 days
- Frost limit
- −6.7 °C
Cultivation
Prefers a moderately heavy loam with a generous amount of compost and sand added and a very sunny position. Dormant plants can withstand temperatures down to about -6°c so long as this is preceded by cool weather in order to harden off the plant. The bitter orange is often grown for its edible fruit in warm temperate and tropical zones, there are many named varieties. 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.
Propagation
The seed is best sown in a greenhouse as soon as it ripe after thoroughly rinsing it. 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, July/August in a frame. Layering in October.
Edible uses
Fruit - raw or cooked. The rind of the fruit is often used as a flavouring in cakes etc. An oil obtained from the seeds contains linolenic acid and is becoming more widely used as a food because of its ability to reduce levels of cholesterol in the blood. The flowers are used for scenting tea. An essential oil from the dried peel of immature fruits is used as a food flavouring.
Medicinal uses
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. Both the leaves and the flowers are antispasmodic, digestive and sedative. The fruit is antiemetic, antitussive, carminative, diaphoretic, digestive and expectorant. The fruit peel is bitter, digestive and stomachic. The seed and the pericarp are used in the treatment of anorexia, chest pains, colds, coughs etc. The essential oil is used in aromatherapy. Its keyword is 'Radiance'.
Material uses
This species is much used as a rootstock for the sweet orange, C. sinensis, because of its disease resistance and greater hardiness. Grown as a hedging plant in N. America. A semi-drying oil obtained from the seed is used in soap making. Essential oils obtained from the peel, petals and leaves are used as a food flavouring and also in perfumery and medicines. Neroli oil, mixed with vaseline, is used in India as a preventative against leeches.
Habitat
Original habitat is obscure, possibly a back cross involving C. maxima X C. reticulata.
Native range
Tropical Asia?