Evergreen buckthorn is also known as Italian buckthorn or rhamnus. It is a serious threat to coastal areas, as it can form thick stands and interfere with native plant regeneration. Find out how to recognise this plant and check out our tips for control
On this page: Why evergreen buckthorn is a pest, identifying features, how to recognise evergreen buckthorn, responsibility for control, controlling evergreen buckthorn, further information
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Why evergreen buckthorn is a pest
Evergreen buckthorn can quickly take over stream and forest margins and disturbed forests, changing the structure of native ecosystems. It is a serious threat to coastal areas, as it can form thick stands and interfere with native plant regeneration.
Evergreen buckthorn is a multi-stemmed evergreen shrub and is tolerant of dry or exposed conditions. It produces a lot of berries from a young age, which are dispersed by birds. It may also grow from suckers.
Evergreen buckthorn originates from the Mediterranean and was introduced to New Zealand as an ornamental plant. It is common in Auckland and on islands in the Hauraki Gulf. At the moment, evergreen buckthorn is limited in the Waikato region and is only in a few localised sites in Hamilton City.
- Leaves can be variable. They are dark green, glossy on top, oval to elliptic and up to 6 cm long. The edge of the leaves can be smooth or with blunt or sharp teeth.
- Can be distinguished from natives by the two small holes at the leaf base and the 'buckthorns' - matching bumps - on the top of the leaves.
- Young shoots are angular, purplish and hairy.
- Flowers are greenish in colour and in small clusters.
- Flowers are 3 - 4 mm in diameter and without petals.
- Individual plants are usually separate gender (male or female).
- Fruits grow up to 7 mm long. They grow in clusters and are a glossy dark red colour, changing to black when ripe.
How to recognise evergreen buckthorn
Evergreen buckthorn is sometimes confused with native plants such as coprosmas. As it is a nondescript plant with variable features, it can be hard to identify. It looks like a shrub or small tree around five metres tall, but can grow up to 10 metres, or may be stunted in growth in exposed places. It has thick foliage with glossy green leaves and small, green, fragrant flowers from May to November. Glossy red berries turn black when ripe.
Responsibility for control
Waikato Regional Council's Regional Pest Management Strategy declares evergreen buckthorn to be a total control plant pest for the entire Waikato region. Waikato Regional Council is responsible for controlling this plant and working with land occupiers to eradicate it.
If you think you have seen evergreen buckthorn, please call 0800 BIOSECURITY (0800 246 732) to report it to your local plant pest contractor.
Controlling evergreen buckthorn
Waikato Regional Council aims to eradicate evergreen buckthorn from the Waikato region. Removing established plants and detecting any new infestations early is vital to achieve this goal.
Small plants up to 30 cm can be uprooted, taking care to grub out all roots. Physical control is ineffective for larger plants, as they readily grow from stems or re-sprout from roots.
Cut stump treatment
Cut stumps and all stems coming from the base and treat immediately with a suitable herbicide such as Vigilant® gel or glyphosate.1
Spraying the foliage of small plants all over is effective. Metsulfuron (such as Escort) or Triclopyr (such as Grazon) are good for stump or spray treatment.
When using herbicides:
- read the instructions on the manufacturer's lable closely
- always wear protective clothing
- always minimise the risk to desirable plants
- contact the supplier for further advice.
For further information and advice contact your local plant pest contractor.
For enquired on policy and prcedural matters call Waikato Regional Council's Freephone 0800 800 401
For more information on plant pests, please visit the Weedbusters website.
Visit our Waikato Regional Pest Management Strategy.
'What makes a pest a pest? - A guide to Waikato's pest management future' download order or pick for free from our offices.
Pick up or order 'Plant me instead - Plants to use in place of common pest plants' for free from our offices.
Download the National Pest Plant Accord.
Pick up or order 'Poisonous plants and fungi in New Zealand - A guide for parents, schools and child minders' for $15 from our offices.
Although this content has been prepared in good faith from a number of sources believed to be reliable, Waikato Regional Council does not give any warranty that all information contained is accurate or complete, or that advice given will be appropriate in all circumstances. Mention of product trade names implies neither endorsement of those products nor criticisms of similar products not mentioned.