Monday, January 18, 2010

Olea europaea subsp. africana – Wild olive


The Olea africana is a small, neat evergreen tree with a dense spreading crown of shiny grey-green to dark green foliage that is silvery underneath. This has to be one of our most versatile trees as it tolerates a wide variety of growing conditions as can be seen by the extensive distribution throughout the country. At this time of the year, when water is at a premium, and strong winds and searing heat create extremely difficult growing conditions for many plants, the Wild Olive comes into it’s own, as it is able to withstand the harshest conditions. As an added bonus, the sprays of whitish flowers are lightly scented and the fruits attract an interesting assortment of fruit eating birds to the garden.



BASIC TREE DETAILS


Botanical Name: Olea europaea subs. africana
Common Name: Wild Olive
Genus: Oleaceae
RSA National Tree No’: 617

LANDSCAPING USES

This attractive, compact, slow - growing tree is an excellent screen plant and a good shade tree, even in a small garden. As it requires minimum maintenance, it makes an ideal subject for street planting, parks, schools, housing and office complexes and even golf courses. Olea africana has been used as an effective stabiliser to prevent erosion of sand dunes and has been planted in very dry areas to provide fodder for stock and game. Avoid planting the Wild Olive too close to swimming pools and walls as the roots may occasionally be aggressive.

TREE SPECIFICATIONS

Height: 8-9m
Spread: 6-12m
Deciduous/Evergreen: Evergreen
Growth Habit: Olea africana occurs in a wide range of habitats from rocky hillsides to stream banks.
Bark: The bark is rough grey to brown, occasionally peeling off in strips.
Foliage: The leaves of the Wild Olive are narrowly oblong to elliptic, glossy grey-green to dark green above and silvery below due to a dense covering of silver to brown scales.
Flowers: The white to cream lightly scented flowers appear in loose terminal heads from October to February.
Fruit: The 10x8mm purplish black ovoid fruits appear from March to July.
Seed: Each fruit contains a single brownish oblong seed which germinates readily.

GROWING REQUIREMENTS


Growing regions: The Olea africana is widespread throughout the country.
Growing conditions: The slow growing Wild Olive tolerates even the most difficult growing conditions but benefits from being planted in a large hole with plenty of compost, good mulch and moderate quantities of water.
Best season: Spring - Summer
Hardiness: This exceptionally hardy tree is drought, wind and frost resistant and withstands temperatures from 5 to 40C.
Propagation: The Wild Olive propagates easily from seed but hard wood cuttings can be taken and rooted in moist river sand using a rooting hormone.
Growth rate: Slow, about 250mm – 400mm per year.

INTERESTING FEATURES

The Olea africana has many well known medicinal applications. The leaves are used to make teas and infusions which are traditionally used to treat various ailments such as eye infections, high blood pressure, sore throats and kidney problems. The early settlers in the Cape used the fruit to treat diarrhea. The juice from the fruit can also be used to make ink. The beautiful, finely grained, golden brown wood has long been much sought after for making fine furniture and ornaments as well as strong, durable fence posts.

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