Managing plant pests

According to the New Zealand Biodiversity Strategy, plant pests or weeds are one of the greatest threats to biodiversity in New Zealand.

Many pretty exotic ferns, herbs, shrubs and trees planted originally as “ornamentals” have turned into invasive weeds that interfere with native plant regeneration, alternative plant communities, and destroy valuable habitat for native plants and animals. Weed control is costing taxpayers millions of dollars each year to prevent exotics from dominating entire ecosystems.

Environment Canterbury has determined that different types of pest plants warrant different "control regimes". These regimes take into account the most appropriate means of addressing the present and potential adverse impacts of these plants.

Total Control Pest Plants

Strategy rules

Land occupiers and other persons shall not sell, propagate or distribute any plant or part thereof of 'Total Control' Pest Plants. A breach of this rule creates an offence under Section 154(r) of the Biosecurity Act 1993. Technical Method: The Regional Council will carry out control operations to eradicate pest plants listed in the 'Total Control' programme prior to seeding in an efficient and cost effective manner. Appropriate physical or chemical means will be utilised.

Pest plants:

Progressive Control Pest Plants

Strategy rules

In relation to the following rules, land occupiers must also comply with these rules on any adjoining roads as described in Section 6 of this Strategy (PDF 6.09 MB).
Pest plants:
Containment Control Pest Plants

Strategy rules

Rules are unique to each identified plant in this category, however in addition, land occupiers must also comply with these rules on any adjoining roads as described in Section 7 of this Strategy.

The species specific rules can be found under the related pest.

Pest plants:

Restricted Sale Programme

A large number of organisms have now been designated by central government as “unwanted organisms”. This means that it is an offence under sections 52 and 53 of the Biosecurity Act to sell, propagate or distribute those organisms anywhere in New Zealand.

Restricted pest plants are restricted in a similar way to “unwanted organisms” in that land occupiers and other persons are not able to sell, propagate, or distribute them. These are listed in the Canterbury Pest Management Strategy under the Restricted Sale Programme. 

Strategy rules

Rule 9.3.3

Land occupiers and other persons shall not sell, propagate or distribute any Restricted Pest or part thereof.

A breach of this rule creates an offence under Section 154(r) of the Biosecurity Act 1993 and may initiate the regulatory procedures set out in Chapter 12.

Pest plants:

            * = Known to be present in Canterbury as at 1 July 2003 

Biodiversity Pest Programme Plants 

This programme seeks to protect biodiversity values in targeted areas by reducing or eliminating the threats imposed by certain plants (and animals).  It does not impose obligations on land owners/occupiers to control these plants in all instances.

Strategy rules

Land occupiers and other persons shall not sell, propagate, or distribute any banana passionfruit, bell heather, Darwin’s barberry, egeria, lagarosiphon, and phragmites or parts thereof.

A breach of this rule creates an offence under Section 154(r) of the Biosecurity Act 1993 and may initiate the regulatory procedures set out in Chapter 12.

Pest plants:

* = not covered by strategy Rules for Biodiversity Pests or listed as Unwanted Organism to prevent sale, propagation or distribution.

We're undertaking a full review of the Canterbury Regional Pest Management Plan, as required by the Biosecurity Act. Read the proposed plan.

Identified pests and management strategies

For more detailed information please see the Canterbury Regional Pest Management Strategy 2011 - 2015 (PDF File, 6.09MB).

Boneseed (Chrysanthemoides monilifera)

Boneseed, like many of our environmental weeds, was first introduced to New Zealand for use as an ornamental plant. Native to South Africa, a lack of pests and disease in New Zealand has allowed it to grow unchecked.

Background

Boneseed is now recognised as a plant pest throughout New Zealand and is included in Canterbury’s Regional Pest Management Strategy for Biodiversity Pests. The objective for boneseed, or salt bush as it is sometimes known, is removal of all existing plants from areas outside the Port Hills and a 20% reduction of infested areas within the Port Hills area over the next 10 years.

Description

Boneseed is an evergreen shrub reaching up to 3 metres. The leaves are dull green, toothed and covered with a cottony down. Daisy-like flowers are produced in bright yellow clusters from late winter until late summer. Boneseed gets its name from its hard, bone-coloured seed. This seed has a thin, fleshy cover - initially green but changing to black upon ripening. Up to 50,000 seeds per plant can be produced in a year and can remain viable for up to 10 years. Seed dispersal is by birds and water.

Why is it a problem?

A tolerance of dry, infertile soils allows boneseed to colonise and establish easily in coastal areas. Its vigorous growth will displace desirable plants, shade out native seedlings and reduce or prevent public access to coastal and beach areas. It is highly flammable and will regenerate prolifically after fire. 

Control

Control of boneseed is relatively easy. Hand pull small plants. Larger plants should be cut just above ground level and the stump immediately treated with an appropriate herbicide. Removed plants should be taken to refuse stations, or composted if all seeds are removed. Follow up care will be needed as any seed remaining on the ground will germinate rapidly once the soil is disturbed and the area is opened to light.

Related documents:

Broom (Cytisus scoparius, C. multiflorus, Teline monspessulana)

Gorse and broom first arrived in New Zealand in the early 1800s. Seed was brought in by English settlers to grow plants for hedging. 

Background

Gorse and broom first arrived in New Zealand in the early 1800s. Seed was brought in by English settlers to grow plants for hedging. A lack of natural control agents in New Zealand in combination with high seed production, unpalatability to stock, and invasive, colonising growth habitats have allowed gorse and broom to become the widespread problems they are today.

Control

Firstly establish the plant(s) are not a New Zealand native broom species.

Chemical control

Foliar spray: An all year round method depending on chemical used and weather conditions. The optimum spray time is from spring to summer when plants are in leaf and actively growing. Foliar spraying is a useful technique for large infestations and scattered plants. Note: Plants need to be covered on all sides with spray for an effective kill.

Cutting and stump treating: An all year round method. Useful technique in ecologically sensitive sites (e.g., rocky outcrops). Cut the stump as close to the ground as possible and apply chemical to the fresh wound with an appropriate herbicide. This method is effective and reduces harm to desirable species.

Herbicide active ingredients registered to control broom & gorse

  • Picloram & Trichlopur mix—A selective herbicide, it doesn’t kill grass but will kill broadleaf weeds. Picloram has a residual control effect on legumes. During periods of slow growth or when growth is dormant (e.g., winter spraying) or stressed, hot, dry, dusty, frosty or salty conditions or when plants have been slashed or grazed, the addition of penetrant to spray mix is recommended.
  • Trichlopyr — A broad spectrum systemic herbicide. Does not damage grass. Also controls broadleaf weeds in turf. Best results are achieved when applied during periods of active growth. No residual control effect.
  • Metsulfuron — A non-hormone herbicide.  It can be used in winter but it takes longer for plants to turn off.  Has a residual control effect. Can cause damage to some trees.
  • Glyphosate — A non-selective herbicide i.e., it will kill most plants that it comes in contact with. To work effectively broom & gorse plants need to be actively growing and not under drought stress with clean foliage (not dusty!) at time of spraying. Note: For gorse — do not treat plants stressed by drought, grazing or previous herbicide treatment. A surfactant must be added or poor results will occur! Rates are only recommended for handgun application in the Agrichemical manual. Glyphosate is inactivated on contact with the soil thus no residual weed control effect.

For choosing the best chemical for your location and situation, contact your local chemical supplier or contractor. Always follow the manufacturer's instructions when using chemicals and prevent spray from entering water ways and contacting the soil. If spraying near waterways, contact your local Regional Council to check if what you intend to do is permitted or will require a permit.

Mechanical control

Slashing/trimming: A useful method to prevent plants seeding along roadsides. This method requires control at least once annually as the plants do not die but will re-sprout (all year round method).
Pulling/digging: Useful in ecologically sensitive sites with scattered small plants (all year round method). Ensure minimum soil disturbance as disturbance encourages seed germination. Leave plants on site to rot down.
Cultivation/Grazing: Cultivation encourages seed germination and must be followed by either blanket spraying or intensive grazing. Over sowing with grass seed and applying fertilisers to improve grass growing conditions can also help to reduce broom seedling re-growth.

Biological control

A good option for large block infestations that are not likely to be sprayed (over 50sqm in area) to reduce plant vigour. Note biological controls assist in reducing plant vigour and rate of spread rather than killing and controlling a broom infestation. Contact your Regional Council (Environment Canterbury) or Landcare Research for more information on broom bio control agents for your area.

Maintain a dense pasture sward to reduce competition from weeds like gorse and broom. Eradicate gorse and broom before seed is produced. Spot spraying, or cutting and immediate stump treatment is useful for isolated plants. Cut stumps must be treated (with herbicide) while the cut is still wet to allow the absorption of herbicide.

Larger infestations can be slashed. Burning encourages seed germination and must be followed by blanket spraying or heavy grazing. Sheep will only graze gorse at the soft seedling stage (about 6–8 weeks). Spraying of large infestations is successful but 100% coverage of each plant is essential.

Biological control for gorse and broom may be an option to assist in containing large infestations. Insects are available at specific times of year and agents work together to reduce plant vigour and seed production. However, biological control is unlikely to kill plants and so does not achieve compliance with the requirements of the Regional Pest Management Strategy.

Follow-up control work will be necessary with all options.

Related document:

Management strategy

Gorse and broom are containment control plants in Canterbury’s Regional Pest Management Strategy. The objective for gorse and broom, over the duration of the strategy, is to prevent infestation of land that is presently free of gorse and broom.

  1. Land occupiers shall eliminate broom infestations that cover up to 50 square metres in area and are greater than five metres from other broom infestations exceeding 50 square metres in area on the land that they occupy. 
  2. For the purpose of this rule, eliminate means the permanent preclusion of the broom plant’s ability to set viable seed.
  3. Land occupiers shall eliminate broom infestations on the land that they occupy within 10 metres of any adjoining property occupied by another land occupier where that adjoining property is clear of, or being cleared of, broom infestations within 10 metres of the boundary between the properties.
    For the purpose of this rule eliminate means the permanent preclusion of the broom plant’s ability to set viable seed.
  4. (c) Land occupiers and other persons shall not sell, propagate or distribute any broom plant or part thereof. A breach of any of these rules creates an offence under Section 154(r) of the Biosecurity Act 1993 and may initiate the regulatory procedures set out in Chapter 12.

Land occupiers are exempted from the provisions of these rules for the following:

  • the requirement to eliminate broom when present as a hedge within a property; and
  • the requirement to eliminate broom when present as a hedge on a boundary provided that the top and sides of the hedge are trimmed each year after flowering but before seed set to minimise seeding.

Land occupiers may apply for an exemption from any of the above rules in accordance with the procedures set out in Chapter 12.

Chilean Needle Grass (Nassella neesiana)

Chilean needle grass is a pest plant which poses a significant threat to the sustainability of farming in Canterbury, and to our environment. Environment Canterbury has declared Chilean needle grass as a pest in Canterbury’s Regional Pest Management Strategy. 

Background

Chilean needle grass is an invasive weed that out-competes productive pasture grasses and takes over large areas if left uncontrolled. It is unpalatable to stock when it is seeding (November-January), reducing the number of stock that can be carried during this period. Its seeds have a sharp, needle-like tip which attaches easily to stock and can penetrate skin and muscle. This can cause painful abscesses for the animal, and can lead to a downgrading of pelts, meat or wool. 

Description

Chilean needle grass is typically found growing on sunny faces in dry grassland areas.

It is most easily identified from late October until March, when it is seeding. Seeds are a reddish, purple colour with a sharp, needle like tip and long twisting tails. 

Where is it found?

Chilean needle grass is widespread in Marlborough and Hawkes Bay, and has been found on a small number of sites in North Canterbury.

It currently infests about 3700 hectares, and has the potential to affect up to 15 million hectares nationwide.

Control

What do I do if I think I’ve found it on my property?

If you think you have found Chilean needle grass on your property, or think that you have bought contaminated seed, stock or feed, report it to Environment Canterbury immediately. A Biosecurity Officer will visit your property to identify the plant and give you help and advice on how to manage it.

How do I stop it spreading to my property?

Chilean needle grass seeds are heavy, and are not easily wind-dispersed. The seed is sharp, and spreads by attaching itself to anything that brushes past the plant. People, animals, vehicles, machinery and equipment, as well as soil, mud and contaminated feed can all carry Chilean needle grass seed.

To prevent Chilean needle grass spreading to your property, put basic vehicle hygiene and farm biosecurity practices in place.

How do I control it on my property?

Chilean needle grass can be difficult to control once established. A range of physical and chemical control methods, tailored specifically to your property may be required. You will also need to put strict hygiene and biosecurity protocols in place to prevent Chilean needle grass leaving your property and infesting other areas. For advice on control methods for your property, contact Environment Canterbury.

Further information

The Chilean Needle Grass Awareness Programme is a joint programme partnered by Environment Canterbury, Hawkes Bay Regional Council, Marlborough District Council and the Ministry for Primary Industries.

Related documents

Chilean needle grass documents

Management strategy

Land occupiers and other persons shall not sell, propagate or distribute any Chilean needle grass plant or part thereof.

A breach of this rule creates an offence under Section 154(r) of the Biosecurity Act 1993 and may initiate the regulatory procedures set out in Chapter 12.

In accordance with section 80D(5) of the Biosecurity Act 1993, exemption to rule 6.3.5 may only be granted for the purpose of scientific research.

Gorse (Ulex europaeus)

Gorse and broom first arrived in New Zealand in the early 1800s. Seed was brought in by English settlers to grow plants for hedging. 

Background

Gorse and broom first arrived in New Zealand in the early 1800s. Seed was brought in by English settlers to grow plants for hedging. A lack of natural control agents in New Zealand in combination with high seed production, unpalatability to stock, and invasive, colonising growth habitats have allowed gorse and broom to become the widespread problems they are today.

Description

Sharply spiny shrub to 2-3 m tall with woody erect or spreading stems which are many-branched in younger plants but become bare at the base as the plant gets older. Leaves are reduced to spines, new leaves less so. Spines are deeply furrowed. Pea-like yellow flowers (13-20 mm long) appear from May to November (occasionally all year round), followed by hairy seed pods (13-25 mm long) which turn black when mature and explode to release seeds.

Control

Firstly establish the plant(s) are not a New Zealand native broom species.

Chemical control

Foliar spray: An all year round method depending on chemical used and weather conditions. The optimum spray time is from spring to summer when plants are in leaf and actively growing. Foliar spraying is a useful technique for large infestations and scattered plants. Note: Plants need to be covered on all sides with spray for an effective kill.

Cutting and stump treating: An all year round method. A useful technique in ecologically sensitive sites (e.g., rocky outcrops). Cut the stump as close to the ground as possible and apply chemical to the fresh wound with an appropriate herbicide. This method is effective and reduces harm to desirable species.

Herbicide active ingredients registered to control broom & gorse

  • Picloram & Trichlopur mix — A selective herbicide, it doesn’t kill grass but will kill broadleaf weeds. Picloram has a residual control effect on legumes. During periods of slow growth or when growth is dormant (e.g., winter spraying) or stressed, hot, dry, dusty, frosty or salty conditions or when plants have been slashed or grassed, the addition of penetrant to spray mix is recommended.
  • Trichlopyr — A broad spectrum systemic herbicide. Does not damage grass. Also controls broadleaf weeds in turf. Best results are achieved when applied during periods of active growth. No residual control effect.
  • Metsulfuron — A non-hormone herbicide. It can be used in winter but it takes longer for plants to turn off. Has a residual control effect. Can cause damage to some trees.
  • Glyphosate — A non-selective herbicide i.e., it will kill most plants that it comes in contact with. To work effectively broom & gorse plants need to be actively growing and not under drought stress with clean foliage (not dusty!) at time of spraying. Note: For gorse — do not treat plants stressed by drought, grassing or previous herbicide treatment. A surfactant must be added or poor results will occur! Rates are only recommended for handgun application in the Agrichemical manual. Glyphosate is inactivated on contact with the soil thus no residual weed control effect.

For choosing the best chemical for your location and situation, contact your local chemical supplier or contractor. Always follow the manufacturers instructions when using chemicals and prevent spray from entering waterways and contacting the soil. If spraying near waterways, contact your local Regional Council to check if what you intend to do is permitted or will require a permit.

Mechanical control

Slashing/trimming: A useful method to prevent plants seeding along roadsides. This method requires control at least once annually as the plants do not die but will re-sprout (all year round method).
Pulling/digging: Useful in ecologically sensitive sites with scattered small plants (all year round method). Ensure minimum soil disturbance as disturbance encourages seed germination. Leave plants on site to rot down.  
Cultivation/Grazing: Cultivation encourages seed germination and must be followed by either blanket spraying or intensive grazing. Over sowing with grass seed and applying fertilisers to improve grass growing conditions can also help to reduce broom seedling re-growth.

Biological control

A good option for large block infestations that are not likely to be sprayed (over 50sqm in area) to reduce plant vigour. Note biological controls assist in reducing plant vigour and rate of spread rather than killing and controlling a broom infestation. Contact your Regional Council (Environment Canterbury) or Landcare Research for more information on broom bio control agents for your area.

Maintain a dense pasture sward to reduce competition from weeds like gorse and broom. Eradicate gorse and broom before seed is produced. Spot spraying, or cutting and immediate stump treatment is useful for isolated plants. Cut stumps must be treated (with herbicide) while the cut is still wet to allow the absorption of herbicide.

Larger infestations can be slashed. Burning encourages seed germination and must be followed by blanket spraying or heavy grazing. Sheep will only graze gorse at the soft seedling stage (about 6–8 weeks). Spraying of large infestations is successful but 100% coverage of each plant is essential.

Biological control for gorse and broom may be an option to assist in containing large infestations. Insects are available at specific times of year and agents work together to reduce plant vigour and seed production. However, biological control is unlikely to kill plants and so does not achieve compliance with the requirements of the Regional Pest Management Strategy.

Follow-up control work will be necessary with all options.

Related document:

Management strategy

Gorse and broom are containment control plants in Canterbury’s Regional Pest Management Strategy. The objective for gorse and broom, over the duration of the strategy, is to prevent infestation of land that is presently free of gorse and broom.

  1. (a)  Land occupiers shall eliminate gorse infestations that cover up to 50 square metres in area and are greater than five metres from other gorse infestations exceeding 50 square metres in area on the land that they occupy.
    For the purpose of this rule eliminate means the permanent preclusion of the gorse plant’s ability to set viable seed.
  2. (b) Land occupiers shall eliminate gorse infestations on the land that they occupy within 10 metres of any adjoining property occupied by another land occupier where that adjoining property is clear of, or being cleared of, gorse infestations within 10 metres of the boundary between the properties.
    For the purpose of this rule eliminate means the permanent preclusion of the gorse plant’s ability to set viable seed.
  3. (c) Land occupiers and other persons shall not sell, propagate or distribute any gorse plant or part thereof. A breach of any of these rules creates an offence under Section 154(r) of the Biosecurity Act 1993 and may initiate the regulatory procedures set out in Chapter 12.

Land occupiers are exempted from the provisions of this rule for the following:

  • the requirement to eliminate gorse when present as a hedge within a property; and
  • the requirement to eliminate gorse when present as a hedge on a boundary provided that the top and sides of the hedge are trimmed each year after flowering but before seed set to minimise seeding.

Land occupiers may apply for an exemption from any of the above rules in accordance with the procedures set out in Chapter 12.

Nassella Tussock (Nassella trichotoma)

Nassella tussock is extremely adaptable and grows in a wide range of habitats. It will displace other plant species. 

Background

Nassella tussock is extremely adaptable and grows in a wide range of habitats. It will displace other plant species.

Description

How to identify nassella tussock

  • Flower heads are purple and carried on slender stalks from October to December. They are erect when young and droop over leaves when mature.
  • Seeds are small, oval and purplish-brown with a bristle at the tip. Nassella tussock is most obvious to the untrained eye when flowers or seeds are present.
  • Leaves are bright green and upright in small plants, becoming duller and more drooping as plants mature. Leaf tips are whitish during winter. Leaves feel rough when rubbed from tip to base.
  • Roots are deep, fibrous and matted, making even small plants difficult to pull out. Stem bases are whitish and separate easily like shallots. When squeezed, the base feels very hard.

Where does it grow?

Nassella will grow almost anywhere. It prefers sunny, dry sites with poor vegetation cover and light soil but as the seed is so easily dispersed, expect to find it in any situation.

Nassella tussock factsheet (PDF 2.39 MB)

Why is it a problem?

Nassella tussock is extremely adaptable and grows in a wide range of habitats. It will displace other plant species. A mature nassella tussock can produce up to 120,000 seeds which are able to disperse over long distances. Some nassella tussock seeds can remain in the soil for more than a decade. Seeds can be wind and water borne, carried via animals, human beings (on clothing), on machinery and in agricultural seed.

Nassella tussock is unpalatable to stock. If not controlled, shading caused by nassella’s drooping foliage and overgrazing of other species soon result in displacement of palatable pasture plants. Nassella was first recognised as a problem in the 1940s and in the 1950s some farmers were forced to abandon their properties because of it.

Nassella tussock is difficult to recognise and distinguish from other tussocks and sedges, both native and introduced. Nassella tussock is costly to eradicate. 

Control

The easiest method to control small infestations is by grubbing. This should be carried out prior to flowering as once flowers are present, even if the plant is grubbed, the seed will still develop and remain viable. All roots should be removed from the ground and excess soil shaken off. Chemical application with a glyphosate product can be useful for dense infestations and should be applied during the growing season.

Under Canterbury’s Regional Pest Management Strategy, land occupiers must complete a control programme to prevent nassella tussock plants from seeding. The control is to be completed by the 30th of September every year for all parts of Canterbury, (except those areas as identified on the map below which are to be completed by the 31st of October every year).

Management strategy
  1. Land occupiers shall, on all the land they occupy, complete a control programme to prevent nassella tussock plants from seeding by:
  2. Land occupiers and other persons shall not sell, propagate or distribute any nassella tussock plant or part thereof.

A breach of any of these rules creates an offence under Section 154(r) of the Biosecurity Act 1993 and may initiate the regulatory procedures set out in Chapter 12. An exemption to any of the above rules may be sought by any person in accordance with the procedures set out in Chapter 12 of the Strategy.

Nodding thistle (Carduus nutans)

Nodding thistle is common throughout the North and South Islands (except Westland). Abundant in summer, it grows in pasture, lucerne and crop plantings, waste places and road sides.

Background
Nodding thistle is classified as a ‘Containment Control pest’ in the Canterbury Regional Pest Management Strategy (2005-2015). Strategy rules require land occupiers to clear nodding thistle at least 40 m from neighbouring boundaries, stock water and irrigation races.
Description
Identification
  • Annual or biennial thistle with red/purple flowers that appear from November to February.
  • Flowers held on tall flower stalks (75 cm or more tall) and can droop down nodding in the wind.
  • The flower head is surrounded by spiny-tipped, small, scale-like leaves that curve backwards.
  • Leaves are deeply divided into triangular lobes with spiny tips. Leaves have a whitish midrib near where the leaf meets the stem.
  • The rosette leaves (at the base of the thistle) are narrow and lobed with spiny edges
Why is it a problem?
Nodding thistle can form dense stands of up to 150 000 plants per hectare. It obstructs livestock movement and prevents access to neighbouring pasture plants. Mature plants can produce up to 10 000 seeds per plant which have a high germination viability (60-80%) and can survive in the soil for a long time. It can also be an issue for certified seed growers as seed contaminated with nodding thistle cannot be exported.
Control
There are a number of insect bio control agents that can reduce nodding thistle vigour. These include the nodding thistle crown weevil, receptacle weevil and gall fly. For more information on bioc ontrol agents refer to Landcare Research
Management strategy
  1. Land occupiers shall eliminate nodding thistle infestations:

    • on the land that they occupy within 40 metres of any irrigation race or stockwater race; and
    • on the land that they occupy within 40 metres of any adjoining property occupied by another land occupier where that adjoining property is clear of, or being cleared of, nodding thistle within 40 metres of the boundary between the properties.

    For the purpose of this rule eliminate means the permanent preclusion of the nodding thistle plant’s ability to set viable seed.

  2. Land occupiers and other persons shall not sell, propagate or distribute any nodding thistle plant or part thereof.

    A breach of these rules creates an offence under Section 154(r) of the Biosecurity Act 1993 and may initiate the regulatory procedures set out in Chapter 12.

Old man's beard (Clematis vitalba)

Old man’s beard is a vigorous growing vine which forms a tangled smothering mass over trees and shrubs blocking out light and eventually killing supporting plants.

Background

Old man’s beard is a vigorous growing vine which forms a tangled smothering mass over trees and shrubs, blocking out light and eventually killing supporting plants.

One plant is capable of blanketing an area of 180 m2. It seeds profusely and the seed can remain viable in the soil for several years. Stems can provide up to 10 m of growth in a season.

Introduced from Europe as a decorative plant, old man’s beard has developed into a major weed problem particularly in the central regions of New Zealand.

Description

Old man's beard is a deciduous vine - it sheds its leaves in winter.

Leaves

Vary from 50 mm to 150 mm in length.

  • Variable shapes: serrated, oval, heart-shaped or lance-shaped.
  • Stems opposite each other on vine.
  • 5 leaflets per stem.
  • Other clematis species generally have three leaflets.

Flowers

White/greenish to yellow/white in colour.

  • Approximately 2 cm diameter.
  • Generally in clusters.
  • December through to April.

Seeds

Sets seed around April.

  • Dispersed during autumn/winter period.
  • Have long plume-like tails which aid dispersal by wind or water.

Vines

Vines may grow to 15 cm in diameter or larger.

  • Young vines are ribbed and often purple in colour.
  • Older vines are woody, often grey/brown in colour.
  • Older vines flake when bent. 
Control

Vines climbing shrubs, trees and hedges:

  1. Search — and trace all vines back to ground level
  2. Clear — a small area around the base of the vines
  3. Cut — all vines as close to the ground as possible
  4. Treat — freshly cut stumps with an undiluted herbicide such as:
    • Glyphosate (Roundup, Network Glyphosate 360 etc.)
    • Woody Weed Killer
    • Vigilant
    • Banvine

    A small paint brush is a useful tool for painting stumps.When used incorrectly herbicides can be harmful. Follow the instructions on the container label.

  5. Finally — ensure that the hanging vines are clear of the ground so that they cannot take root. They may be left in the tree to break down.

Vines scrambling over the ground and large areas of old man’s beard:

Seek advice from a Biosecurity Officer at Christchurch, Timaru, Kaikoura, Cheviot, Amberley, Darfield or Little River.

Non-chemical control:

Will only succeed if all roots are dug out. When vines touch the ground they usually develop extra roots and all of these must be removed for control to be successful. Note: Just cutting the vines will result in rapid regrowth.

Check the site each spring for regrowth and new seedlings.

Related document

Old Mans Beard, clematis vitalba, Factsheet (PDF File, 2.72MB)

Management strategy

Land occupiers shall destroy old man’s beard infestations that cover up to 100 square metres in area and are greater than 20 metres from other old man’s beard infestations exceeding 100 square metres in area on the land that they occupy.

Land occupiers shall destroy old man’s beard infestations on the land that they occupy within 20 metres of any adjoining property occupied by another land occupier where that adjoining property is clear of, or being cleared of, old man’s beard infestations within 20 metres of the boundary between the properties.

Purple loosestrife (Lythrum salicaria)

Gardeners can play an important role in helping stamp out a potentially serious weed from the country’s damp spots and waterways.

Background

The Department of Conservation (DOC), Ngai Tahu, Environment Canterbury and the Christchurch City Council are working together to try to eradicate purple loosestrife (Lythrum salicaria) from Canterbury. Purple loosestrife thrives in damp places, particularly river or lake margins, and can clog drains and irrigation ditches. It also crowds out native plants, and changes habitat for wetland birds and fish.

It is one of the worst agricultural and environmental weeds in North America, invading large areas and displacing other plants and potentially it could do the same here.

Fortunately there are very few places in New Zealand so far where purple loosestrife is growing in the wild.  However, if no action is taken, this species may spread out of control. Purple loosestrife has the potential to be as serious a problem as weeds like old man's beard, gorse and broom.

All the small purple loosestrife sites found so far in Canterbury have been successfully controlled.  There is an ongoing control programme for the larger sites, such as Cockayne Reserve (a Christchurch City Council reserve near the Avon River/Ōtākaro).  The control on these larger sites has been even better than expected, confirming that it should be possible to beat this weed.

Purple loosestrife was until recently sold as a garden plant. However, it is now declared an unwanted organism in New Zealand and consequently is banned from sale, propagation or division.

Purple loosestrife can produce over 2 million seeds per plant per year and most seeds last at least 3 years.  Seeds are dispersed by water, but may also be spread by wind and birds and on machinery.  Because it has so many seeds, once established, purple loosestrife can quickly form a dense stand that excludes most other vegetation.

Description
  • The plant can grow to 3 metres high with up to 50 stems per plant (usually square in cross-section).
  • It flowers from December to February with showy spikes of purple flowers at the end of the stems.
  • The leaves and stems die off in winter, to re-sprout in spring.
Control

If you suspect you have purple loosestrife or think you have seen it, please contact Environment Canterbury Biosecurity via Customer Services on ph: 0800 324 636 (0800 EC INFO) or email ecinfo@ecan.govt.nz and leave a details with your name, contact details and location of sighting.  A good identification tip is to roll the stem between your finger and thumb, purple loosestrife stems are distinctively angled rather than round. 

Ragwort (Senecio jacobaea)
Ragwort is commonly found on roadsides, riversides and damp pastures. The recent shift in some Canterbury farming practices from dry land farming to dairying has resulted in more irrigation and consequently wetter pastures. These conditions favour ragwort growth. Care is required to prevent ragwort from becoming the same problem that nodding thistle has become in some areas.
Background
Ragwort is toxic to stock. It acts as a cumulative poison that builds rapid fatal toxicity in horses and cattle. In sheep the toxin can take three years to become fatal. The toxin in ragwort eventually causes irreparable liver damage in animals. If ragwort is included in hay or silage, it still retains its toxic attributes while becoming more palatable to stock and therefore more dangerous. Ragwort is a prolific seeder producing up to 150 000 seeds per plant (up to 90% can be viable). The seeds are predominantly spread by wind and water but also by stock and in hay.
Description
  • Biennial or perennial plant up to 1.2 m tall.
  • Grows in a rosette form in the first year. (Can stay as a rosette for up to 3 years.)
  • Bright yellow-golden daisy flowers (summer to autumn) are held in large clusters on up-right, leafy, branched stems.
  • Stems are ridged and purplish in colour.
  • Parachute-like seeds.
  • Leaves on mature plants are deeply divided and are ‘raggedy’ in appearance.
  • Leaf underside often purple.
  • Unpleasant smell when plant bruised.
Control
Mechanical control
Grubbing or pulling is best done when the plant is at a full to late flowering stage when the roots are less likely to re-grow. Any flower heads present should be burnt at a high temperature to destroy any developed seed heads. Pasture management It is important to maintain a competitive pasture sward to prevent the establishment of ragwort. Mowing ragwort is not recommended as it encourages the plant to grow multiple stems and makes it more difficult to kill.
Chemical control
Stock should be removed from the area until the sprayed plants have died as ragwort becomes more palatable to stock after spraying. Spot spraying should be carried out before flowering as plants are more difficult to kill following flowering and once seed has been produced. If considering chemical control, please contact your local farm merchandise supplier for advice on available chemicals and recommendations for application.
Biological control
Several bio control agents have been introduced to attack ragwort in New Zealand. The most successful agents to date have been the ragwort flea beetle and the cinnabar moth. Although these insects have established and impacted on ragwort in a number of areas, they have failed to establish in colder sites. Hence the ragwort plume moth and ragwort crown boring moth have recently been introduced (first releases in 2006) as they are more tolerant of cooler climatic conditions and therefore have a greater chance of establishing in areas where the flea beetle and cinnabar moth have struggled. It is mainly the larvae of these insects that cause the most damage to ragwort by eating the foliage, stem and root material.
Management strategy
  1. Land occupiers shall eliminate ragwort infestations:

    • on the land that they occupy within 40 metres of any irrigation race or stockwater race; and
    • on the land that they occupy within 40 metres of any adjoining property occupied by another land occupier where that adjoining property is clear of, or being cleared of, ragwort within 40 metres of the boundary between the properties.

    For the purpose of this rule eliminate means the permanent preclusion of the ragwort plant’s ability to set viable seed.

  2. Land occupiers and other persons shall not sell, propagate or distribute any ragwort plant or part thereof. A breach of these rules creates an offence under Section 154(r) of the Biosecurity Act 1993 and may initiate the regulatory procedures set out in Chapter 12.

Variegated thistle (Silybum marianum)      

Management strategy
  1. a) Land occupiers shall eliminate variegated thistle infestations:
    • on the land that they occupy within 40 metres of any irrigation race or stockwater race; and 
    • on the land that they occupy within 40 metres of any adjoining property occupied by another land occupier where that adjoining property is clear of, or being cleared of, variegated thistle within 40 metres of the boundary between the properties.

For the purpose of this rule eliminate means the permanent preclusion of the variegated thistle plant’s ability to set viable seed.

  1. (b) Land occupiers and other persons shall not sell, propagate or distribute any variegated thistle plant or part thereof.  

    A breach of these rules creates an offence under Section 154(r) of the Biosecurity Act 1993 and may initiate the regulatory procedures set out in Chapter 12. 
Velvetleaf (Abutilon theophrasti)
Velvetleaf has been found in the South Island - in North Canterbury and Central Otago fodder beet crops.  The Ministry for Primary Industries (MPI) is investigating how it got there and how widespread it is. To date, it has only been found in fodder beet crops.  This South Island arrival appears to be recent. MPI is working with Environment Canterbury and other partner organisations to manage the situation. Three sites have been identified in North Canterbury.

Velvetleaf is one of the world's worst cropping weeds, affecting many arable crops by competing for nutrients, space, and water. It is an Unwanted Organism in New Zealand.

If you find this pest please call the MPI free hotline – 0800 80 99 66 immediately and photograph the plant and mark its location so it can be found again.
For the latest UPI updates and identification information go to: MPI Velvetleaf 
Wilding conifers - Lodge pole pine (Pinus contorta
Lodge pole pine is one of the most prolific ‘wilding conifers’ which are rapidly invading the high country in certain locations. It is a very frost-hardy and drought tolerant tree, producing lots of light, wind-dispersed seeds at an early age. It can invade open forest, native sub-alpine grassland, shrub, and herb communities— even above the native tree line. In the long-term, lodge pole pine may displace these communities entirely. Dense stands also increase fire risk.
Background
It is a very frost-hardy and drought tolerant tree, producing lots of light, wind-dispersed seeds at an early age. It can invade open forest, native sub-alpine grassland, shrub, and herb communities— even above the native tree line. In the long-term, lodge pole pine may displace these communities entirely. Dense stands also increase fire risk.
Description
  • Short needles in pairs; needles are usually twisted
  • Small cones with a sharp spike on each cone segment
  • Old empty cones remain attached to branches
  • Cones can be seen on trees as young as six years old
Control
Remove seed-producing trees and isolated scattered plants first. Pull small seedlings out by the roots. Cut bigger trees near ground level and either apply herbicide to the cut stump or ensure all green needles are removed. After initial control, follow-up checking of the area for new re-growth will be required for several years. Use all herbicides in accordance with the manufacturer’s instructions and ensure no herbicide comes into contact with other plants, the soil or waterways. Check the New Zealand Wilding Conifer Management Group website for more information about lodge pole pine, other wilding conifers and how to control them.
Management strategy

Strategy rules for self-seeded wilding conifers

Land occupiers shall take all steps, in relation to self-seeded wilding conifers on their land, as are reasonably necessary to prevent the communication, release or other spread of those self-seeded wilding conifers.

For the purposes of this rule, communication means passing on, transmitting or transporting in any way

Land occupiers may apply for an exemption from the above rule in accordance with the procedures set out in Chapter 12. Applicants shall provide evidence to Environment Canterbury in support of an exemption application. Such evidence should at least provide a risk assessment of the spread from any retained area of wilding conifers, the risk of wilding establishment in the surrounding areas and neighbouring properties and a proposed control programme including methods and timelines.

Aquatic pest plants

The invasion of aquatic pests such as water weeds into Canterbury's waterways affects us all.  If you fish, whitebait, water ski, row, kayak or just swim, these water weeds can affect your success, safety and enjoyment in our waterways. Waterweeds ruin valuable ecosystems by inhibiting growth of native water plants and reducing likely spawning areas for many types of fish.

How to prevent aquatic weed invasions

CHECK

Check boats, trailers and other water equipment for any plant material and remove.  Even if the plant appears dry and dead it may still survive and start a new infestation.  Leave debris at site or if you find any later, treat and dispose of in the rubbish.  Do not wash down drains.

CLEAN

Wash all equipment thoroughly with an appropriate decontamination solution before putting it in any new water way, eg. nets, machinery, footwear and clothing.

DRY

If you can't clean your gear, (or animals), restrict use to a single waterway OR dry completely to the touch inside and out and then leave dry for AT LEAST another 48hours.

What else can I do?

  • Decide not to throw any aquarium or pond material into waterways.  Instead put all unwanted pond material on the garden or compost - your small oxygen weed may become the next threat to many native fish, birds, and plants.
  • Decided not to give plants / plant parts away to others until you are sure of what they are and their growth habits are not a threat to our waterways.
  • Make wise decisions on how to avoid increasing nutrient levels in waterways from fertiliser.  High levels of nutrients running into waterways tends to encourage vigorous growth of some weeds. 

Aquatic weeds of concern