Olive

About this weed

This common tree of Perth gardens and public areas originated in Europe but in recent years has become a significant problem in bushland. In South Australia it is a serious bushland weed that forms thickets that eliminate native vegetation. Because the fruit is easily distributed by birds, it is now becoming a problem in Perth bushland. Despite the warnings, the olive is still widely sold as a drought tolerant small tree useful in Perth gardens and commercial olive plantations are still being planted.

Description

The olive is a well recognized tree growing to 15 m high. It produces sprays of small white flowers in late spring followed by a massive fruit set. The fruit is green at first but turns black when ripe. The fruit and seed is dispersed by birds and mammals. The seedbank persists for 5+ years. Fire kills young plants but older plants will resprout following fire.

Impact on Bushland

It is a serious bushland weed that forms mixed age thickets that can virtually preclude native plant recruitment. Eastern Australian populations have been introduced from South Africa (ssp. cupidata) and South Australian and Western Australian populations have originated in Europe (ssp. europea).

Location

Can be found in bushland and road sides in the South-West Province but prefers more Mediterranean climate. It can also be seen around older settlements.

Priority for removal

High: major threat to the conservation values of Banksia woodlands and other native vegetation.

Management (hand)

Hand pull or dig out seedlings and small plants ensuring removal of all roots any time of the year.

Management (herbicide)

For mature plants cut to base and paint 50% Glyphosate or apply 250 ml Access in 15 L of diesel to base 50 cm of trunk (basal bark). Monitor sites for seedling recruitment. Read the manufacturers’ labels and material safety data sheets before using herbicides. Optimal months for treatment or spraying are from March to May and October to December.

Flowering month/s

September, October, November

Flower colour/s

White

Information source

https://florabase.dpaw.wa.gov.au/browse/profile/6503

Additional information

https://florabase.dpaw.wa.gov.au/weeds/swanweeds/

Hussey, B.M.J., Keighery, G.J., Dodd, J., Lloyd, S.G. and Cousens, R.D. (2007) Western weeds. A guide to the weeds of Western Australia, Second Edition, The Weeds Society of Western Australia, Victoria Park, Western Australia.

Olive images