Growth Habit: Gorse is a prickly, perennial, evergreen shrub which, if left undisturbed, will, in favourable conditions, grow to a height and diameter of 2-3 metres in four to five years. All it’s stems and leaves are prickly, ending in a sharp spine. The small dark green leaves are stiff and covered with a waxy coat.
Type of Plant: Evergreen, woody shrub.
Fruit/Seed: Hairy, grey pods each produce 2 to 6 brown to black seeds. A mature infestation can produce up to 6 million seeds per ha each year. Seeds have a hard, water-resistant coating allowins them to remain viable in the soil for over 30 years.
Dispersal: When seed pods burst, seed can be thrown up to 6 metres from the parent plant. Seed is also spread by ants and water. Seed can be carried into new areas in soil attached to machinery and boots. Gorse regenerates prolifically after fire from soil stored seed.
Distribution: Gorse is present in most agricultural and urban areas throughout Tasmania. If allowed to grow and spread unchecked, the weed can quickly smother large areas making them totally inaccessible. Gorse can colonise poorer soils. In Tasmania it covers large areas of hilly and stony ground, where control is difficult and expensive. On fertile soils, Gorse can occupy land that could be more productive in good pasture. It also takes over the understorey in native vegetation.
Near buildings and on fence lines it constitutes a serious fire hazard during the summer months. It can also harbour rabbits and other vermin.
On the other hand, Gorse can provide emergency feed and stock shelter. It is thought to provide a safe refuge for vulnerable native animals (such as bandicoots) from feral and domestic cats in areas where there is little native understorey left.
Status: Gorse is a Declared Secondary Weed and a Weed of National Significance.
- Gorse is a serious environmental weed. Once established, it competes strongly with native vegetation, alters fire regimes and reduces biodiversity.
- Mature plants will shoot from damaged or burnt stems and roots.
- Gorse is spread only by seed. Good hygiene is essential if Gorse free areas are to be protected.
- Once established in an area, Gorse is difficult to eradicate due to the long term viability of soil stored seed.
- Gorse will invade pasture areas, impacting productivity for grazing.
Similar Plants: Some native plants are also prickly in nature but they do not have the pea shaped flowers.
- At a minimum, you must control the spread of Gorse to neighbouring properties. This means controlling plants within 10 metres of property boundaries, waterways, drainage lines, roadways and other transport corridors.
- Ensure you patch of Gorse is not the last remaining patch of habitat for native species such as the threatened Eastern-bared Bandicoot. If it is, consider a staged approach to control, while replanting native species to replace lost habitat.
- Hygiene (all year). Gorse can be easily spread by machinery especially along roadsides. Care must be taken to ensure good hygenic practices in Gorse infested areas. Some steps – any road grading equipment should work from clean areas into infested areas and then be cleaned on the infested area. All quarries and gravel dumps should be kept free of any environmental weeds. It is an offense to import Gorse as it is a Declared Weed.
- Grazing (Mar – Apr & Aug – Nov). Most important periods for grazing are April to July and September to November when Gorse is in flower. Grazing will reduce flowering and seeding. The use of goats on burnt Gorse has controlled infestations.
- Cultivation (Jan – Apr & Aug – Nov). A late summer early autumn cultivation will increase seedling germination of Gorse. This cultivation must be followed by a later cultivation to kill the germinated seedlings.
- Chaining (May – Aug). The use of chaining requires reasonably moist soils in order to extract as much of the Gorse root system as possible.
- Grubbing (Jun – Sept).
- Crushing (Aug – Nov).
- Burning (Jan – Apr & Jul – Nov). Burning is a good initial step in controlling Gorse. A burn from August to November is the optimum time to reduce biomass and from January to April to increase seed germination. Another control method is required in conjunction with a burn for control of Gorse.
- Mulching (May – Sept).
- Tree Planting (all year). In certain areas, the establishment of trees forming a canopy will give long term control of Gorse.
- Spot Spraying (all year). For herbicide application refer to Gorse Declared Weed Leaflet.
- Basal/Cut Stump (Aug – Mar).
N.B. Always check the herbicide label before use.