- Plant type
- Shrub or small tree
- Status in NSW
- Should not be sold in parts of NSW. All land managers have a general duty to reduce its spread.
African olive is a hardy small tree first brought to Australia in the 1800s for hedges and as rootstock for edible olives. Birds spread the fruit into bushland, where its dense shade crowds out the native plants underneath.
How to identify it
African olive is an evergreen shrub or small tree, usually 5 to 10 metres tall, with a dense canopy. Look for:
- leaves in opposite pairs, 6 to 10 cm long and narrow, glossy grey-green on top and green or yellow-brown underneath, often with a small hooked tip
- tiny creamy white flowers in spring and summer
- olive-shaped fruit 15 to 30 mm long, green with white spots when young and purple-black when ripe
- silvery-green young stems and rough grey bark on older trunks
The edible olive has leaves that are silvery underneath and have pointed tips. Native mock olives have much larger, leathery leaves.
Where it grows
African olive copes with a wide range of conditions and can grow in dense shade. Its worst infestations in NSW are around south-west Sydney and the Hunter. It grows in bushland, along creeks and from old hedges, so finding and removing it early keeps it from taking hold in our valley.
Why it's a problem
- Its dense shade suppresses native understorey plants and can permanently change the make-up of bushland.
- It can harbour pests and diseases of commercial olives.
- Its fruit is not edible.
How to control it
Control plants before they fruit, and follow up on regrowth and new seedlings.
- Hand pull or dig out seedlings, removing all of the root.
- Cut and paint: cut stems no higher than 10 cm above the ground and apply herbicide to the cut immediately.
- For trunks over 10 cm across, cut into the sapwood all the way around and apply herbicide straight away (stem injection).
- Small plants can be sprayed, covering all of the foliage.
Damaged trees send up suckers, and plants re-shoot after cutting or burning, so check back and treat the regrowth. Always follow the herbicide label and contact your local council weeds officer for advice.
Safety and disposal
- Wear gloves and eye protection when cutting and applying herbicide.
- Remove and bag any fruit before you cut a tree down, so you do not spread the seed.
Stopping it coming back
- Remove old hedges and plantings before birds spread them into bushland.
- Check creek lines and bush edges near known trees each year for new seedlings.
- Replant cleared areas with local native species.
