Quick Facts

Quick facts

• Originally from north Africa and western Asia, African Olive (Olea europaea subsp. cuspidata) is an evergreen shrub or tree with larger leaves, 6–10 cm long, 10–25 mm wide, oblong to oval in shape, dark grey-green above, yellowish-brown below, with the leaf-apex with a hooked tip.
• Introduced as a rootstock for the cultivated varieties of tree that produce edible and oil bearing fruits.
• African Olive is highly invasive can form dense thickets in parkland or bushland where it crowds out other species.
• African Olive is common in  New South Wales, also occurring in south-east Queensland, and rare in Victoria and South Australia.
• It has become naturalised in temperate to semi-arid areas, with winter rainfall, tolerant of long summer droughts.
• Can establish in undisturbed pristine native vegetation, over decades forming dense populations excluding native plants and animals.
• It is locally dispersed by birds and animals, mostly introduced pests, and more widely through the nursery trade, and plantations.
• Can be controlled by physical and mechanical means, herbicides with many techniques used depending on age and density of plants.
• Control of established populations requires integrated techniques over many years.

What Does It Look Like?

What is it?

African Olive (Olea europaea subsp. cuspidata) is a well-branched evergreen shrub or tree growing 2–10 (rarely to 15) m high without prickles or spines. It is very similar to European  Olive (Olea europaea subsp. europaea). African Olive has larger leaves, 6–10 cm long, 10–25 mm wide, narrowly oblong to oval in shape, occurring in pairs along the branches. Leaves are dark grey-green above, yellowish-brown below, with the edges of the leaf curling back, the leaf-base narrowing gradually to wedge-shaped, with the leaf-apex with a hooked tip, with main venation (mid-rib ) obvious on upper surface with some lateral veins just visible. The leaf stalks are up to 10 mm long.

Flowers are cream or white in colour borne in many-flowered clusters on branches 5–6 cm long, which arise from the base of the leaf stalks. Each flower is small, with four petals, 4–5 mm long with a tube 1–2 mm long, with lobes c. 3 mm long that are re-flexed back at maturity. Flowers have 2 male stamens, with a single female two lobed stigma. Flowers are surrounded by a calyx (green buds) of 4 triangular sepals each about 1-2 mm long.

The fruits are ellipsoidal to almost globular, smooth, purple-black when mature, 1.5–2.5 cm long, with an edible flesh surrounding a single stone or seed which is brown to black (Green 1986; Jeanes 1999; Green 2002).

For further information or assistance with the identification of African Olive, contact the herbarium in your state or territory.

Flower colour

White

Growth form (weed type/habit)

Tree, Shrub

Where it currently grows? Preferred habitat

African Olive grows in areas receiving at least 500 mm rainfall per annum, with cool winters and hot, relatively dry summers. It prefers modified habitats where soil nutrients are moderate. It has become naturalised along roadsides, in bushland, waste areas and disturbed sites (Parsons & Cuthbertson 1992). DPI NSW (2019) states that African olive grows throughout NSW with the worst infestations  around southwest Sydney and the central Hunter Valley. It has naturalised along the whole of the western slopes from north to south.

In the 1800s it was introduced to Australia as a hedging plant and as root stock for edible olives. African olive first naturalised along coast between Milton and Lismore. It is a tropical wild olive that comes from eastern Africa  (Parsons & Cuthbertson 1992). 

Are there similar species?

African Olive is of very similar appearance to European Olive (Olea europaea subsp. europaea). European Olive has larger fruits with a thicker flesh (Green 2002).

Why Is It A Weed?

What are its impacts?

African Olive impacts both environmental and agricultural land.

Agriculture: The plant may be effectively controlled by grazing, as stock find it is quite palatable. It can become a major weed of parklands, where grazing is low or absent (Parsons & Cuthbertson 1992).

Native ecosystems: It can alter the composition of native vegetation, becoming a dominant component of forest or woodland under-storey (Cuneo & Leishman 2006).  It invades bushland produces dense shade and suppresses native under-story plants, can permanently change plant diversity in bushland, may also harbor diseases and pests of commercial olives.

How does it spread?

African Olive is dispersed by seed. Over short distances, dispersal is likely to be by birds and soil movement. Long-distance spread is usually through the nursery trade (Parsons & Cuthbertson 1992; Cuneo & Leishman 2006).

What is its history in Australia?

African Olive was first introduced to Australia, for horticultural purposes, in the mid 19^th century (Cuneo & Leishman 2006).

How To Manage It?

Best practice management

The control of African olive is similar to the of the European Olive. African Olive can be controlled by physical means, both with hand tools for smaller plants and mechanically with machinery for larger plants sometimes in conjunction with herbicides as part of integrated controls. In parkland or bushland, control may be achieved by physical, mechanical or chemical means. Effective control requires a long-term plan as trees are hardy, have a vigorous and persistent root systems and a substantial long-lived seed bank, with regrowth and ongoing germination requiring a continued control effort over many years for mature and established populations.

Non-chemical control: African Olive plants are readily controlled on farms by increasing grazing. Smaller seedling to sapling to 30-10 cm tall can be hand pulled when the soil is moist through enabling removal of the large tap root with disturbed soil should be tamped down after removal preventing further germination of olives or other weeds. During drier times or for larger plant to 1.5 metres, may be grubbed out with a mattock or chip-hoe. These and lager trees and established old populations and shrubs can be cut down and treated with chemicals will normally require repeated herbicide treatment to kill the plants.  Drill and fill Holes are drilled 2-3 cm deep, into the lignotuber and trunk, about 40 mm apart and for a minimum of three rows. A registered herbicide is then applied within 20 seconds to the holes.  Frill and fill Grooves are cut with a hatchet or chainsaw around the lignotuber and trunk, 2-3 cm deep, about 40 mm apart (being careful not to ringbark the plant), at a 450 angle and for a minimum of three rows (the more the better). Fill each groove or cut with herbicide within 20 seconds. Suitable for small and mature trees. Can be treated all year, however avoid hot periods when the plant may be stressed. Removing mature trees and populations usually resulting in heavy seedling regeneration so followup work over many years is likely required. Mature trees and their stumps can be bulldozed or mechanically removed, however the potential damage this may cause to soils must be weighed up (Government of South Australia 2016).

Chemical control: For smaller plants to 1.5 metres tall spot spraying is effective with a registered herbicide at label rates, and the Cut and swab method where the trunk is cut as low as possible to the ground and painted (swab) with a registered herbicide within 20 seconds. Mature plants are best controlled by applying herbicides to cut stumps or basal parts of the plant that have been exposed by peeling back the bark. Seedlings and small plants can be treated by herbicide spraying. In all cases, follow-up is important to control resprouting and seedling germination (Parsons & Cuthbertson 1992; Muyt 2001). Direction for controlling Wild Olives (Olea europaea) using the basal bark treatment can be seen at, Government of South Australia (2016). All techniques should be monitored and any regrowth or new seedlings treated via the hand pull, grub, basal or spot spray techniques.

Please see the Australian Pesticides and Veterinary Medicines Authority for chemical information http://www.apvma.gov.au

Does it have a biological control agent?

NO

When does it grow? (lifecycle/growth calendar)

African Olive is a perennial plant. Seeds germinate in autumn, and African Olive grows for several years before flowering commences (Parsons & Cuthbertson 1992). Flowers are borne in summer, and fruits ripen in the winter (Cuneo & Leishman 2006).

Where Is It Found?

Which states and territories is it found?

NSW, QLD, SA, VIC.

What areas within states and territories is it found?

African Olive is widely naturalised in coastal or tableland areas of New South Wales and southeast Queensland (AVH 2021; Parsons & Cuthbertson 1992). It has a limited distribution in South Australia and is near absent from Victoria (AVH 2021; Hussey et al. 2007).

Where does it originate?

The geographical origin of African Olive is from South Africa to north-east Africa, and in southern Asia (Green 2002).

National And State Weed Listings

Is it a Weed of National Significance (WONS)?

NO

Where is it a declared weed?

NSW, SA, WA

Government weed strategies and lists – Weeds Australia

Is it on the National Alert List for Environmental Weeds?

NO

Government weed strategies and lists – Weeds Australia

Is it on the Agricultural Sleeper List?

NO

Government weed strategies and lists – Weeds Australia

Names And Taxonomy

Main scientific name

Olea europaea subsp. cuspidata

Other scientific names (synonyms)?

• Olea africana Mill.
• Olea chrysophylla Lam.
• Olea cuspidata Wall. ex G.Don
• Olea europaea subsp. africana (Mill.) P.S.Green

Does it have other known common name(s)?

African olive, Olive, Olive tree, Small-fruited olive, Wild olive