What does it look like?
Tree privet is a broad-leaved, medium-sized, hairless shrub or small tree that can grow up to 15 metres tall. It’s evergreen and highly shade-tolerant. The dark green, glossy leaves are arranged in opposite pairs along the stems and can grow up to 12 cm long.
From November to March, tree privet produces small, fragrant, creamy-white flowers in clusters. These are followed by bluish to purplish-black berry-like fruits, around 6 x 5 mm in size, each coated with a powdery ‘bloom.’ The terminal flower clusters develop into dense berry clusters, with a single shrub or tree capable of producing between 100,000 and 10 million seeds. These seeds are primarily dispersed by birds.
Why is it a problem?
Tree privet is capable of forming dense stands that inhibit native plant recruitment and displace vulnerable shrub species. It creates thick carpets of seedlings on the forest floor and can grow through the understorey to eventually dominate and replace canopy trees across a wide range of forest types.
The berries are highly viable and are toxic to humans. They may also be poisonous to native fauna, particularly insects. Tree privet is fast-growing and extremely resilient. It’s tolerant of shade, frost, damage, grazing, and a wide range of well-drained soil types. It thrives in both damp and drought-prone conditions, withstands salt and wind, and can live for over 100 years in moderate to high temperatures.
Seeds are widely dispersed by birds, as well as through vegetation dumping and soil movement. Common seed sources include roadsides, farm and urban hedges, gardens, and neglected land.
The pollen and scent of privet may be an irritant to allergy sufferers or those with respiratory issues such as asthma.
Control methods
Physical control
Pull or dig seedlings out all year round. Leave on site to rot down.
Herbicide
- Cut low and treat stump immediately (all year round) using 250ml glyphosate (360g/l) per 1L water or 5g metsulfuron-methyl (600g/kg) per 1L water.
- Drill and fill (all year round) using a 10-12mm drill bit. Drill one downward sloping hole every 200mm around the base of the trunk and fill with undiluted glyphosate or 20g metsulfuron-methyl (600g/kg) per 1L water. Extra safety precautions must be taken if using undiluted herbicides.
- Frilling: With a sharp chisel or axe, make a deep cut into the sapwood at regular intervals around the base of the tree, taking care not to ring-bark the plant. Immediately saturate the cuts with 250ml glyphosate per 1L water or 5g metsulfuron-methyl (600g/kg) per 1L water.
- Foliar spray (spring-autumn) using 5g metsulfuron-methyl (600g/kg) + 10ml penetrant per 10L water or 100ml glyphosate (360g/l) + 10ml penetrant per 10L of water.
CAUTION: When using any herbicide or pesticide, PLEASE READ THE LABEL THOROUGHLY to ensure that all instructions and safety requirements are followed.
More information
- Tree and Chinese Privet are listed as Sustained Control pests in the Hawke’s Bay Regional Council Regional Pest Management Plan 2018-2038.
- These are subject to Plan Rule 11.
Related links
Management Programme
National Pest Plant Accord (NPPA)
The NPPA is designed to prevent the sale, distribution and propagation of a set list of pest plants (the Accord list) within New Zealand. If allowed to spread further, these pest plants could seriously damage the New Zealand economy and environment.
More informationSustained Control Programme
To provide for ongoing control of the subject, or an organism being spread by the subject, to reduce its impacts on values and spread to other properties.
Unwanted Organism
An unwanted organism is any organism that's capable of causing harm to natural or physical resources (like forests and waterways) or human health. A number of introduced pests in New Zealand are classed as unwanted.
Rules
Plan rule 11
An occupier of land within the urban area will, upon receipt of a direction from an authorised person, destroy all privet on their land.
For the purpose of this Plan Rule, the urban area is defined as any property accessed from a street with a permanent speed zone of 50km or less.
Taxonomies
FamilyOleaceae
TypePlants
GroupShrub
HabitatLand
Management ProgrammeNational Pest Plant Accord (NPPA)Sustained Control ProgrammeUnwanted Organism
RulesPlan rule 11
