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Common Name: Bitter Orange

General Information

Poncirus trifoliata is a deciduous shrub that can grow up to 3.00 metres tall.
The plant is harvested from the wild for local use as a food and medicine. It is sometimes grown as an ornamental, where it can be used as a hedge.

Known Hazards

None known

Botanical References

, ,

Range

E. Asia - C. and S. China, Korea.

Habitat

Hedgerows[]. Woods in mountains and hills in Korea[].

Properties

Edibility Rating
Medicinal Rating
Habit	Deciduous Shrub
Height	3.00 m
Growth Rate	Slow
Pollinators	Insects
Self-fertile	Yes
Cultivation Status	Wild

Cultivation Details

An easily grown plant, it succeeds in an ordinary garden soil[], preferably well-drained[], but prefers a fertile light sandy soil in a sunny position[, ]. A plant is growing and fruiting well in light woodland shade at Cambridge Botanical Gardens[]. Plants dislike soil cultivation close to their roots and so should either be well mulched to prevent weed growth, or hand weeded[]. Succeeds in poor acid soils[]. Plants also succeed in chalk-laden soils[].
Hardy to about -15°c[]. Plants have survived -30°c of frost without injury according to one report[].
The bitter orange hybridizes with Citrus species and could possibly be used in breeding programmes to produce hardier forms of oranges, lemons etc[, ]. It could also be of value in conferring disease resistance, tolerance of poorer soils and dwarfing characteristics.
The flowers are produced on the previous years wood[]. The whole plant, but especially the flowers[], is strongly aromatic[].
A very ornamental plant[, ], the fruits are freely formed in south-western Britain[, ]. A hedge at Wisley in a semi-shaded position fruits heavily in most years[]. Another report says that warm autumns are required if the plant is to fruit freely. Fertile seed is produced after warm summers[].
Plants are relatively short-lived, deteriorating after about 25 years[].

Edible Uses

Fruit - cooked. A bitter and acrid flavour, but it can be used to make a marmalade[, , ]. The fruit is also used to make a refreshing drink[, ]. The freshly picked fruit yields little juice but if stored for 2 weeks it will yield about 20% juice[], which is rich in vitamin C. Yields of up to 14 kilos of fruit per plant have been achieved in America[]. The fruit is 2 - 3cm wide[], though most of this is the skin[].

The fruit peel can be used as a flavouring[].

Young leaves - cooked[].

Medicinal

The thorns are used in the treatment of toothache[].

The stem bark is used in the treatment of colds[].

The fruits contain a number of medically active constituents including flavonoids, coumarins, monoterpenes and alkaloids[].
The fruit, with the endocarp and seeds removed, is carminative, deobstruent and expectorant[]. It is used in the treatment of dyspepsia, constipation and abdominal distension, stuffy sensation in the chest, prolapse of the uterus, rectum and stomach[]. It is milder in effect than the immature fruit and is better used for removing stagnancy of food and vital energy in the spleen and stomach[].
The unripe fruit is antidiarrheic, antiemetic, antispasmodic, deobstruent, digestive, diuretic, laxative, stimulant, stomachic and vasoconstrictor[, , , ]. It is used in the treatment of dyspepsia, constipation and abdominal distension, stuffy sensation in the chest, prolapse of the uterus, rectum and stomach, shock[].

Agroforestry Uses:

The plant is very thorny and makes an excellent impenetrable barrier or hedge[, , ], though this barrier is not very dense[]. The plants are very tolerant of pruning[], they are best clipped in early summer shortly after flowering[, ].

Other Uses

Used as a rootstock for Citrus species (oranges, lemons etc)[, ]. It confers an extra 3°c resistance to the cold[].

Propagation

Seed - best sown as soon as it is ripe in a cold frame[]. Cold stratify stored seed for 4 weeks and sow early spring in a greenhouse[]. Prick out the seedlings into individual pots when they are large enough to handle and grow them on in the greenhouse for at least their first winter. Plant them out into their permanent positions in early summer.
Cuttings of half-ripe wood, early summer/July in a frame[].