Friday, January 27, 2012

Olive

Olea
A small genus of close to 20 species of evergreen trees and shrubs that are part of the Oleacaceae family. They are mostly native to the Mediterranean, Asia and Africa.
They prefer full sun; deep fertile well drained soil and long hot summers.
Most species are very drought tolerant once fully established.
They are deer resistant but the trunks of young trees should be protected from rabbits or other gnawing critters.
Propagation is from cuttings, suckers or seed that is soaked for 2 days before sowing.

Olea africana ( African Olive )
Also called Olea europaea subsp. cuspidata. A close relative to Olea europea, which becomes a medium sized tree.
It is native to southern Africa where it is endangered.
Some records include: 90 years - 40 x 70 feet with a trunk diameter of 4.6 feet; largest on record - 60 x 82 feet with a trunk diameter of 13 feet. Some records include: 90 years - trunk diameter of 4.6 feet; It makes an excellent shade tree for an open lawn but keep in mind that its aggressive large root system can damage pools and underground pipes.
The foliage is similar to that of Olea europea but is glossy gray-green above, rusty-brown beneath. The willow-like leaves are up to 3 x 1 inches in size.
The purplish-black fruits are up to an inch in length.
The highly valuable wood is used to make fine furniture.
Hardy zones 9 to 10 ( tolerating as low as 15 F ). Very drought tolerant.
Propagation is from seed. If often self seeds to the extent of being invasive and should not be planted in much of southern Australia where birds will widely distribute the seed.

* photos of unknown internet source



Olea capensis ( Black Ironwood )
A fast growing, large, evergreen tree, reaching a maximum height of 133 feet, that is native to eastern and southern Africa. Some records include: fastest growth rate - 4 feet; 4 years - 15 feet. It makes an excellent landscape tree.
The leaves, up to 4 x 2 inches, are glossy deep green.
The fragrant, white flowers are borne during spring.
The are followed by edible, small, purplish-black fruits, up to 0.6 x 0.3 inches.
The bark is dark gray and fissured.
Hardy zones 9 to 11 preferring full sun though it will tolerate shade.

* photos of unknown internet source



subsp macrocarpa ( Cape Olive )
Also called Olea macrocarpa. A fast growing large tree, reaching a maximum height of 100 feet with a trunk diameter of 5 feet, that is native to southern Africa.
The leaves are up to 4 x 1.5 inches.
The fine timber is highly valued.
Hardy zone 10

Olea cunninghamia ( Black Maire )
A slow growing, medium-sized tree.
The leaves are up to 10 x 0.5 inches in size.
Hardy zones 9.

Olea cuspidata
Some records include: largest on record - 65 x 88 feet with a trunk diameter of 4.5 feet.

Olea europaea ( Common Olive )
A medium-sized, evergreen tree, native to the Mediterranean Sea region is among the worlds most important trees. It also makes a very attractive landscape tree with older plants often having a twisted trunk and gnarled branches. Moderate to fast growing when young; some records include: 4 years - 12 feet; 5 years - 17 feet; 80 years - trunk diameter of 40 x 57 feet with a trunk diameter of 3.5 feet; 100 years - 50 feet; 130 years - trunk diameter of 5.3 feet; largest on record - 100 x 60 feet with a trunk diameter of 11.9 feet. It has been grown in the mildest parts of England but grows slowly there due to cooler summers. One is known to have reached 20 feet in London. Extremely long-lived, the Olive tree has been known to survive as long as 3014 years.
The lance-shaped leaves are up to 4 x 1 inches in size. The foliage is deep gray-green above; silver beneath.
The fruits, up to 1 inch in length, are green, later ripening to black.
They are extremely valuable, and are among the healthiest of all oils for cooking.
Trees generally bear fruit after reaching the age of 10.
Trees need to be planted in groups to achieve good fruit production.
The oil content of the fruit is usually about 25 %. An orchard of Olive can bear up to 2 tons per acre. This tree is extensively grown as a commercial crop in southern Europe, southwest Asia, northern Africa and to a lesser extent in Argentina and the southwest U.S. It also makes an excellent landscape tree for other mediterranean climate regions in the world such as central Chile and southwestern Australia.
In parts of southern Australia it grows too vigorously and spreads too fast, thus becoming a weed.
The dark gray bark on older trees is fissured.
Hardy zones 8 to 10, hot summers are required to fruit production.

* photos of unknown internet source









* photos taken on June 23 2013 @ U.S. National Arboretum, DC

* historical archive photos


'Arbequina'
Hardier ( zone 8a ) and does not need a pollinater to bear fruit.

'Little Ollie'
An attractive cultivar, reaching a maximum size of 12 x 12 ( rarely over 5 ) feet forming a moderate growing, dense rounded shrub. It makes an excellent choice for patio containers and hedging.
The foliage is deep green above, bright silvery-green below.
It does not produce fruit.
Hardy zones 8 +.

'Lucca'
Very vigorous and large growing, producing abundant fruits that are used for excellent tasting oil ( fruits contain around 28% oil content ).
Hardy zones 8 to 10, it is among the more cold hardy Olives.

'Majestic Beauty'
Fast growing, it does not produce fruit so it can be planted as a street tree or to shade the driveway. Not sure about the point of growing a fruitless Olive...I think I'd just grow the real thing and pick all the fruit before they fall.
Hardy zones 8 to 10.

'Manzanillo'
A large tree that can live up to 2000 years, possibly more.
There is attractive, leathery foliage on this cultivar commonly grown in mediterranean climates throughout the world. The abundant, large fruits are purplish-green to black. The fruits are very often sold for eating at your local grocery store.
Hardy zones 8 to 10 ( tolerating at least as low as 12 F ) it is also extremely heat tolerant and is among the best cultivars for the Deep South in the U.S.

'Mission;
Vigorous, reaching up to 40 x 40 feet, and commonly planted in California and in fact the most common cultivar in northern California. The foliage is gray-green.
It is self fertile not needing a pollinator to produce fruit. The flavorful black fruits can be eaten or made into olive oil.
More cold hardy than species ( zones 7b to 10 ). It has been known to tolerate 0 F and resprout after being killed to the ground at -4 F. It is the most cold hardy Olive and can be grown where many other Olives can't be grown.

'Oblonga'
Reaches up to 50 feet, with attractive silvery foliage.
It produces high quality olive oil.
Hardy zones 9 +. It has excellent resistance to Verticillium Wilt.

'Swan Hill'
Fast growing, reaching up to 40 x 30 feet.
Hardy zones 8 to 10.

Olea excelsa ( Picconia )
A handsome, impressive, medium-sized, evergreen tree that is native to the Canary Islands. It can reach a maximum height of 60 feet with a trunk diameter of 3 feet.
The elliptical leaves, up to 4 x 2 inches, are glossy deep green.
Hardy zones 9 to 10, it thrives in England only around Cornwall.

Olea ferruginea ( Indian Olive )
A rounded, evergreen, medium-sized tree, reaching up to 40 feet with a trunk diameter of 2 feet, that is native to the northwest Himalayas. Some records include: 6 years - 12 feet. One year coppice shoots can reach up to 3 feet.
The leaves are up to 4 inches in length.
The fruits are a good source for Olive Oil.
Hardy zones 8b to 10 ( tolerating at least as low as 14 F ).

Olea lanceolata ( White Maire )
A slow growing, small to medium-sized tree that is native to New Zealand.
Some records include: largest on record - 50 feet with a trunk diameter of 3.5 feet.

Olea laurifolia
A large tree, that is native to Africa. It can reach a maximum height of 120 feet with a trunk diameter of 4.5 feet.
The elliptical leaves, up to 4 x 1.5 inches, are glossy green.
The very strong timber is the heaviest wood of any species of tree.
Hardy zone 9

Olea yunnanensis
An extremely rare, elegant, large evergreen tree, reaching a maximum height of 100 ( averaging 40 ) feet, that is native to western China.
The lance-shaped leaves, up to 7 x 3 inches, are glossy mid-green.
The purplish-black fruits are small. Hardy zone 8 to 10 ( reports of 7 ); thriving in the Deep South.

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