Introduction
Gorse is a very spiny dense shrub, which has thousands of showy yellow pea-type flowers that are most abundant in spring and autumn. It grows up to four metres tall, but is more commonly found in two metre tall impenetrable thickets. Very few other plants can survive in these thickets. The flowers are 15-20 millimetres long and form 10-20 millimetre long hairy, grey pods which produce two to six seeds that are explosively ejected as the pod dries.
Native to Europe and originally planted as a hedge, gorse is now a weed of disturbed areas and roadsides around Albany.
The seeds are viable for many years and the seed bank often exceeds 10 000 seeds per square metre.
Control
Gorse is difficult to eradicate and seedlings will keep emerging for many years, thus an integrated control program using a combination of methods is more likely to be successful. Our aim is to conduct an eradication program for Western Australia (WA).
Options
- Roll, hot burn and then cultivate established infestations if possible. Spray with 100 millilitres GrazonTM plus 25 millilitres Pulse® in ten litres of water when the plants are actively growing during spring to autumn. Establish vigorous grasses and fertilise with nitrogen.
- Graze with goats and spot spray trouble spots with GrazonTM. On areas that can’t be grazed, apply GrazonTM annually until few seedlings appear. Two years after the last GrazonTM spraying, re-plant the area with species that will provide complete shade as quickly as possible.
- Control seedlings and small plants manually or spray with 100 millilitres glyphosate (450 grams per litre active ingredient) in ten litres of water or blanket wipe with one litre of glyphosate (450 grams per litre active ingredient) in two litres of water.
- Large individual plants can be controlled by spraying a mixture of 200 millilitres AccessTM in ten litres of diesel on the lower 50 centimetres of each main stem. This is known as basal bark spraying.
Good hygiene practice goes a long way to preventing the further spread of this weed. As larger plants tend to break off and re-grow, burn material from manual control on site if possible. Do not remove soil from a gorse infected site without advice from the Department of Agriculture and Food, Western Australia (DAFWA).
Gorse is declared under the Biosecurity and Agriculture Management Act 2007 (BAM Act) and must be controlled.
Gorse is a weed that spreads slowly and this provides an opportunity for control. The seed spreads mainly by explosive expulsion from the seed pod, water and the movement of topsoil, which means everybody in a community must control gorse together to get lasting results and avoid reinfestation from neighbours.
In the long term, control of gorse will rest with landholders because seed will last in the soil for many years and constant vigilance is required to control seedlings as they appear. The Natural Heritage Trust (NHT) and DAFWA recognise this problem and have provided funding for community training, advice, loan of equipment and supply of herbicides for the control of small infestations.
This should give local landholders the ability and confidence to get on top of ths weed and encourage ongoing surveillance.
Online weed identification training
Login or set up a new account on DAFWAs online training site to access:
- a training course on how to identify gorse and report it.
- training material that you can use to teach community groups how to identify gorse.
Further information
For more information on gorse, search this website or contact the Pest and Disease Information Service.