One of the advantages of olives as a commercial crop is the large amount of fruit they produce. However, this can be a disadvantage as the fruit is easily spread with the potential to germinate and establish in undesirable areas as wild olives. Olive fruit is commonly eaten by birds and foxes who subsequently spread the seed to establish on roadsides, in native vegetation and in
abandoned pastures.
Wild olives cause serious environmental damage in native vegetation where they quickly dominate and smother out most low and medium storey species. This is of particular concern in the 6th Creek catchment due to the large areas of existing native vegetation.
Due to their high levels of oil, olives are also highly flammable and can create a serious fire risk.

Control Methods

In the Mt Lofty Ranges, wild olives are proclaimed under the Animal and Plant Control Act, which requires any spread of
olives from olive plantations to be controlled.

Effective control requires a long-term plan as trees are hardy,  with a vigorous and persistent root systems and a substantial long-lived seed bank. Regrowth and ongoing germination require continued control effort.
Methods for controlling Olives may include the following techniques:
– hand pull;
– grubbing;
– cut and swab;
– drill and fill
– frill and fill;
– spot spray;
– mechanical removal; or
– Basal treatment.

For advice on chemical control techniques contact your nearest Natural Resources Centre.   Refer to the ‘Weed control handbook for declared plants in South Australia’ for detailed advice on chemical control. You can find it on the Biosecurity SA website.

Nicer natives

Southern Cypress-pine   Callitris gracilis
Cylindrical-shaped tree to 5m. Green foliage, dark brown cone fruit. Responds to pruning. Uses: screening, hedging, and to line driveways and paths. Well-drained sandy and limestone soils. Can be used instead of non-native conifers.

Silver Banksia   Banksia marginata
Feature tree 3 to 5m. Leaves green on top, silver below. Yellow flowers on cylindrical cone, spring to autumn. Responds to pruning; can prune to single trunk. Interesting foliage and seed pods.
Uses: feature plant, streetscaping. Slow growing. If foliage yellows apply chelated iron.