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Gorse

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Botanical Name: Ulex europaeus
Other Common Names:

Declarations

 
Class Regions
Class 3Orange City Council,Upper Macquarie County Council
Landholder Responsibilities: The plant must be fully and continuously suppressed and destroyed
Why Is It Bad?: Gorse is a weed of disturbed or degraded agricultural land and native environments. As a Weed of National Significance (WoNS), it is one of Australia's top twenty worst weeds. Gorse forms dense thickets to the exclusion of all other vegetation. The seeds have long dormancy periods, up to 30 years, with disturbance generally required for germination to occur. Infestations also increase nitrogen levels in the soil, affecting the growth of native species. Stands provide harbour for rabbits and other feral animals. They also pose a serious fire hazard as lower, dead branches are retained on the plant.

Identification

Habit: Shrub
Leaves: Leaves are spine-like, alternate, grey-green, 30mm long and 1.5mm wide. They have a waxy coating and end in a yellow point. All branches have a terminal spine-like leaf.
Flowers: There are usually 2 flowering periods per year: autumn and late winter to spring. Flowers are bright yellow, 15-25mm long, and grow in the leaf axil. They are pea flowers and smell like coconut.
Fruit: Due to 2 flowering periods, there are also 2 seeding periods: spring to early summer and autumn. Seed pods are 10-20mm long, 6mm wide, black and covered in fine hairs. Each pod contains 2-6 seeds with seed production reaching 10000 per square metre. The seed pods explode, dispersing seed many metres from the parent plant.
Roots: Roots are woody, mostly shallow with a poorly developed taproot.

Control Methods

Manual Removal: Seedlings or small plants can be handpulled or dug out. Roots should also be removed. Any disturbance will result in mass germinations, follow-up work is required.
Chemical Use: Cut-stump or stem injection methods can be used if the trunk is accessible. Foliar spray is the most common method with numerous herbicides available. Surfactants should be used to help the herbicide penetrate the leaf's waxy coating. Follow-up work will be required for several years.
Fire: Fire can be used to remove dead growth and stimulate germinations to help exhaust the soil seedbank. This must be followed up with treatment of new seedlings with herbicide. This method can be repeated for several years to achieve comprehensive control.
Slashing & Cutting: Slashing can be used to remove dead growth and stimulate germinations to help exhaust the soil seedbank. This must be followed up with treatment of new seedlings with herbicide. This method can be repeated for several years to achieve comprehensive control.
Biological Control: There are four biological control agents available but all have limited levels of effectiveness in NSW's climate. The Gorse seed weevil (Exapion ulicis) feeds on the seeds while in the pods. The Gorse spider mite (Tetranychus lintearius) and Gorse thrips (Sericothrips staphylinus) both act to reduce Gorse's ability to develop by feeding on fresh growth. A new agent, Grose soft shoot moth (Agonopterix umbellana), was released in 2007. As biological control is a slow process, the results of this release are yet to be determined.
Grazing: Sheep and goats will graze seedlings, young plants and regrowth.
Cultivation & Scalping: If the site is arable cultivation, as part of a cropping regime or pasture improvement program, will help to control Gorse. Seed needs to be buried below it's viable depth, and if carried out over 4or 5 years, it can be very effective.
Smothering:
Solarisation:
Competition: Seedlings are susceptible to competition. Competition will not prevent germinations but it will reduce the volume.
Monitoring: Successful treatment programs rely on ongoing monitoring of sites. Regrowth and new seedlings can easily become larger infestations if follow-up treatments are not part of the management program
 




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