Common name: Gorse
Botanical name: Ulex europeaus
Management programme: Sustained control
Originally from Europe, gorse and broom were brought to our country by settlers in the 1800s for use as hedge plants. They soon spread from these original plantings and began invading the landscape.
Why is it a pest?
Gorse is only considered a pest under our pest plan in the gorse and broom-free areas and rural-zoned properties. It forms thick groups of bushes that prevent stock from grazing and is generally seen as a threat to farming values and indigenous vegetation. Gorse is included in the pest plan primarily because of the negative effects outweigh its beneficial attributes.
Gorse will grow anywhere in Otago. Thankfully, large areas of Central Otago and the Queenstown Lakes are mostly clear of infestations. The thickness of infestations depends on how intensely the land is grazed. It is most widespread on lightly-grazed and non-grazed areas. Seed can be spread by water, birds, road-making, gravel extractions, animals and machinery.
While gorse is invasive in many areas, it tends to be less vigorous at higher altitudes. Both gorse and broom seed may lie dormant in the soil for 40-80 years, so monitoring and control will be required for many years.
The sustained control programme aims to provide for ongoing control of the pest to reduce its impacts on values and spread to other properties.
What does it look like?
Gorse is a spiny, woody, deeply rooted, leguminous (part of the pea family) shrub. It grows up to 4m tall with thick stems. Seeds can be pop out up to 5m from pods and the plant can seed twice a year.
Click here to see images
Gorse and broom-free areas
The goal of the pest plan is to sustainably control broom along with gorse, to ensure that land that is free of, or is being cleared does not become infested. This is to prevent negative effects on both production and economic values. To achieve this ORC slightly extended the gorse and broom-free areas from out last plan.
These areas are mainly Otago’s unique high country and tussock grasslands that have never had a major history of these pest plants, and where an invasion of these plants would greatly affect grazing, biodiversity and the landscape. In total, the gorse and broom free areas cover over 50% of Otago.
Click here to see a map of the gorse and broom free areas in our pest plan.
What are the rules?
These are the simplified rules; for the full rules go to page 55 of the Regional Pest Management Plan 2019.
- Everyone within the gorse and broom-free areas must eliminate gorse on the land that they occupy. For those in the new gorse and broom-free areas this rule will not be enforced until March 2024. ORC will give advice and information to anyone in the new areas to make sure they are ready for this rule to come into effect.
- Everyone outside gorse and broom-free areas on rural zoned land, must eliminate gorse 10m from their property boundary where the neighbouring property is eliminating broom 10m on their side of that boundary.
How can I control it?
Control tends be dealing with either single bushes or small isolated infestations.
The options are to:
- Hand pull small plants and dispose of them with your green waste making sure there is a little soil disturbance as possible
- Cut down and treat the stump near the ground using a suitable herbicide gel like Tordon BK containing either metsulfuron triclopyr or glyphosate
- Spray when the plant is actively growing using suitable herbicides such as Tordon or Grazon.
Caution: When using any herbicide or pesticide PLEASE READ THE LABEL THOROUGHLY to ensure that all instructions and safety requirements are followed.
Grazing is not a preferred option as it tends to be short-term control only without completely eradicating the plant. They can still grow, produce seed and spread.
Disclaimer: Mention of product trade names does not endorse these products nor imply criticism of similar products not mentioned. The Otago Regional Council does not give any warranty that the information is accurate or complete or that it is suitable for all circumstances.
Eliminate – The permanent prevention of the plant’s ability to set viable seed.
Land occupier – An occupier is the person who physically occupies the place, the owner of the place and any agent, employee, or other person acting or apparently acting in the general management or control of the place. For example if you are renting a house owned by someone else that does not live on that property, you are the occupier and are responsible for pest management under the pest plan. You can see more about the responsibilities of occupiers (including owners) in section 3.3.1 of the pest plan.