Gorse

Ulex europaeus

What is Gorse?

Gorse is an invasive evergreen shrub that has a reputation as one of New Zealand’s most troublesome agricultural weeds. Its ability to spread and outcompete pasture (and reduce grazing capacity) has severe economic and environmental impacts.

Native to Europe and parts of the United Kingdom, gorse was introduced into NZ early in the 1800s, probably for hedging. Its attractive flowers, longevity (up to 30 years) and adaptable characteristics were (and still are) highly valued across Europe, so it must have seemed sensible at the time to plant it in NZ landscapes. Unfortunately, it quickly escaped to become an invasive weed throughout the country.

Gorse is a spiny shrub that can grow up to 3m tall and 3m wide. Its stems are soft green and furry when young and become brown, woody and covered in numerous spines as they mature. The leaves are covered in a waxy coating, which helps reduce water loss and allows it to thrive in areas with low rainfall. Its distinctive bright yellow flowers appear in spring and late summer-autumn.

Grey-black seed pods appear soon after flowering. They’re 10-20mm long and covered in fine hairs. Each pod contains 2-6 seeds that are readily distributed by livestock, birds, ants, footwear, and waterways. Each plant can produce thousands of seeds annually. Seeds are covered in a water-resistant coating that allows them to remain viable in the soil for 30-50 years.

Gorse thrives in cool temperate climates and will grow on a wide range of soil types, although it prefers acidic soils. It’s a major weed of pasture areas and can also provide shelter for pests, like rodents, rabbits and stoats. Gorse also increases the risk of fires, as it’s highly flammable and the dead dry vegetation provides abundant source of fuel.

Gorse does have a part to play in native bush regeneration; gorse can act as a 'nurse crop' for native trees to become established. As the trees mature, they begin to shade out the gorse and prevent new gorse from germinating underneath them.

How to control Gorse

For large stands of gorse, apply Yates Zero Super Concentrate Weedkiller, with Yates Zero Pulse Penetrant (to defeat the waxy leaf coating) added into the mix. For small areas apply Yates Zero Tough Ready to Use. To control gorse, spray plants when they are actively growing, from spring to mid-summer. Spray foliage and stems thoroughly. Repeat applications may be needed, especially for established thickets. Continue to monitor the area after treatment, as there are likely to be gorse seeds germinating. Re-sprouting gorse is more likely if there is any soil disturbance, e.g. cultivation, changes in soil moisture, or after fire.

Areas impacted by Gorse

• Pasture
• Roadsides
• Creek banks
• Reserves
• Sites with disturbed soil