There are many options available to attack gorse but what method you choose will depend on some of the following circumstances;
- Machinery availability i.e. mulching equipment, spray unit, knapsack
- Own expertise and labour available
- Access to the treatment area i.e. terrain
- Amount of money you have available to allocate to the job
- Amount of area to be treated
The above photo shows the effectiveness of herbicide used on a large infestation of gorse that was sprayed in December 2016 by a contractor. The size of the plants were generally between 0.6 to 1.5 meters tall. Overall excellent results with 99% kill rate of gorse.
I have had experience in using both spraying and mulching control methods. I have found that generally there is only need to spray new seedlings annually after the larger infestations are reduced or removed from the property. When undertaking gorse spraying I usually contact my local Landcare Group and borrow their high volume spray unit.
To get an effective kill of gorse you need to follow the directions for use of the chemical as detailed by the manufacturer, paying particular attention to rain events and the volume of the mix i.e. chemical to water ratio.
I have always mixed a red dye into the spray unit as you can readily see what you have sprayed. In areas where there are many gorse seedlings you can easily miss treating a few. If you miss it this year it will be most likely be twice as big next year and you will need to use more chemical.
The below photo shows gorse that has not had a 100% kill rate and one contributing factor may be that spray coverage over the gorse plants was not thorough enough. Herbicide manufacturer’s instructions for woody weeds are to provide: ’Thorough coverage of foliage to the point of run-off is essential, however avoid excess spraying which is wasteful of chemical’.
Brian Rowe – VGT committee member