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Gorse

http://www.gw.govt.nz/gorse

Gorse

Updated 9 July 2019 12:47pm

Unfortunately, gorse needs little introduction. It is considered by many to be New Zealand’s worst scrub weed.

Credit: Te Ara

‘Gorse is a plant that can be useful: it made good hedges, adds nitrogen to the soil which can be good for forestry, and can act as a nurse crop that native bush can grow up through. And yet, for most of us it is a persistent physical annoyance, that forms large infestations which are hard to eliminate, can prevent the regeneration of natives, and by improving poor soil types can push out some of our native species.’

Katrina Merrifield, Biosecurity Advisor at GWRC.

Why is it bad?

Gorse produces massive numbers of long-lived seeds and grows rapidly. It thrives in most environments as it tolerates hot to cold temperatures, high to low rainfall, wind, salt, damage and grazing, and all soil types.

Gorse seed can lie dormant on the ground for up to 50 years, germinating quickly after mature plants have been removed. It soon regrows from dormant buds on stumps if shrubs are cut without prior herbicide treatment or stump treatment at the same time. Regrowth from buds can also occur after fires. Many herbicides are not very effective on gorse because of the shape of the "leaves" and the thick cuticles on the spines which help prevent absorption of herbicides. 

As gorse spreads it reduces the area available for grazing by livestock on pasture land. It also competes with young forest trees, and makes access to forests difficult for pruning and thinning operations. 

How to tackle it

We control gorse in our region's Key Native Ecosystems to protect each site’s unique plants and animals. You can control this pest on your property with these methods:

  • Cut and treat
    Cut off at the base of the plant and treat the stump with an appropriate herbicide immediately after cutting.
  • Spraying
    Different herbicides are more effective at different times of the year.

For advice on timing, methods and herbicides see Weedbusters. Be sure to closely follow all label instructions.

How to stop it coming back

Once the area is fully clear, plant and mulch to minimise regrowth and support local biodiversity – the plants and animals that naturally occur in the area.

If herbicides have been used, read the label for information about when to replant.

Check the site regularly for seedlings and continue to clear any regrowth.

More information