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Common Name: Olive

General Information

Olea europaea is an evergreen tree that can grow up to 10.00 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

S. Europe - Mediterranean.

Habitat

Woods and scrub in dry rocky places[].

Properties

Edibility Rating
Medicinal Rating
Habit	Evergreen Tree
Height	10.00 m
Growth Rate	Slow
Pollinators	Wind
Self-fertile	Yes
Cultivation Status	Wild

Cultivation Details

Easily grown in a loamy soil[] and tolerating infertile soils[], it prefers a well-drained deep fertile soil[]. A drought resistant plant once established, it succeeds in dry soils[]. Requires a sunny position[]. Tolerates salty air[]. Plants are slow-growing and very long-lived[].
The olive is very commonly cultivated in Mediterranean climates for its edible seed, there are many named varieties[, ]. Trees can produce a crop when they are 6 years old and continue producing a commercial yield for the next 50 years[] - many trees continue to give good yields for hundreds of years, even when their trunk is hollow[]. They succeed outdoors in the milder areas of Britain[], though plants rarely produce fruit when grown in this country[, , ], preferring warm temperate regions with mild moist winters and hot dry summers[]. Some reports say that trees often fruit in south-western England[, ]. Generally, older trees are hardy to about -10°c[, ]. They require the protection of a south facing wall when grown in the London area[].
At least some cultivars are self-fertile[]. Some cultivars have been selected mainly for their fruits whilst others have been selected for their oil[]. 'Mission' is grown for its edible fruits. It is vigorous, prolific and very cold resistant[]. 'Moraiolo' is grown for its oil, it is very hardy and strong-growing[].
Flower production depends on a 12 - 15 week period of diurnally fluctuating temperatures with at least 2 months averaging below 10°c[].
Pruning can encourage non-fruiting water-shoots[]. Weighing down or arching the branches can encourage fruiting[]. The plants fruit best on wood that is one year old so any pruning should take this into account[].
An olive branch is a traditional symbol of peace[], laurel leaves were used by the ancient Greeks to crown winners of the Olympic games[].
Plants have male flowers and bisexual flowers[].

Edible Uses

Olive fruits are widely used, especially in the Mediterranean, as a relish and flavouring for foods. The fruit is usually pickled or cured with water, brine, oil, salt or lye[, , , , ]. They can also be dried in the sun and eaten without curing when they are called 'fachouilles'[]. The cured fruits are eaten as a relish, stuffed with pimentos or almonds, or used in breads, soups, salads etc[]. 'Olives schiacciate' are olives picked green, crushed, cured in oil and used as a salad[]. The fruit contains 20 - 50µ vitamin D per 100g[]. The fruit is up to 4cm long[].
The seed is rich in an edible non-drying oil, this is used in salads and cooking and, because of its distinct flavour, is considered a condiment[, , , , , ]. There are various grades of the oil, the finest (known as 'Extra Virgin') is produced by cold pressing the seeds without using heat or chemical solvents[]. The seed of unpalatable varieties is normally used and this oil has the lowest percentage of acidity and therefore the best flavour[]. Other grades of the oil come from seeds that are heated (which enables more oil to be expressed but has a deleterious effect on the quality) or from using chemical solvents on seed that has already been pressed for higher grades of oil. Olive oil is mono-unsaturated and regular consumption is thought to reduce the risk of circulatory diseases[]. The seed contains albumen, it is the only seed known to do this[].
Leaves[]. No more details are given.
An edible manna is obtained from the tree[].

Medicinal

The oil from the pericarp is cholagogue, a nourishing demulcent, emollient and laxative[, , ]. Eating the oil reduces gastric secretions and is therefore of benefit to patients suffering from hyperacidity[]. The oil is also used internally as a laxative and to treat peptic ulcers[, ]. It is used externally to treat pruritis, the effects of stings or burns and as a vehicle for liniments[, ]. Used with alcohol it is a good hair tonic and used with oil of rosemary it is a good treatment for dandruff[, ]. The oil is also commonly used as a base for liniments and ointments[].
The leaves are antiseptic, astringent, febrifuge and sedative[, ]. A decoction is used in treating obstinate fevers, they also have a tranquillising effect on nervous tension and hypertension[, ]. Experimentally, they have been shown to decrease blood sugar levels by 17 - 23%[]. Externally, they are applied to abrasions[].
The bark is astringent, bitter and febrifuge[, ]. It is said to be a substitute for quinine in the treatment of malaria[].
In warm countries the bark exudes a gum-like substance that has been used as a vulnerary[].
The plant is used in Bach flower remedies - the keywords for prescribing it are 'Complete exhaustion' and 'Mental fatigue'[].

Other Uses

The non-drying oil obtained from the seed is also used for soap making, lighting and as a lubricant[, , ]. The oil is a good hair tonic and dandruff treatment[]. The oil is an effective inhibitor of hydrochloric acid corrosion when coated over steel[].
Maroon and purple dyes are obtained from the whole fresh ripe fruits[].
Blue and black dyes are obtained from the skins of fresh ripe fruits[].
A yellow/green dye is obtained from the leaves[].
Plants are used to stabilize dry dusty hillsides[].
Wood - very hard, heavy, beautifully grained, takes a fine polish and is slightly fragrant. It is used in turnery and cabinet making, being much valued by woodworkers[, , , ].

Propagation

Seed - sow late winter in a shady position in a greenhouse[]. Home produced seed should be given a period of cold stratification first[]. Where possible, it is best to sow the seed as soon as it is ripe in a greenhouse in the autumn. 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, perhaps for their first 2 - 3 winters. Plant them out into their permanent positions in early summer and give them some protection from winter cold for at least their first winter outdoors[].
Cuttings of half-ripe wood, 5 - 10cm with a heel, mid summer in a frame. Good percentage[].