Pampas

Other common names: 'cutty grass'.

On this page:

• Why it is a pest plant
• How to recognise this pest plant
• Responsibility for control
• How to control pampas
• Summary of herbicides and application methods for control
• Further information

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Why it is a pest plant

Pampas is a very invasive grass. It is a serious threat to some natural areas (like sand dunes, stream banks and coastal cliffs) where is can completely replace native vegetation. It is a particular problem on roadsides (reducing visibility), along railways and in newly planted forests. Pampas can be a fire risk due to the large amount of dry matter it produces. It also harbours pests such as rats, mice, rabbits and possums.

There are two species of pampas in New Zealand - common pampas (Cortaderia selloana) and purple pampas (C. Jubata). Both species are native to South America. Infestations of both species are now found throughout the region.

How to recognise this pest plant

Both pampas species are large tussock-forming grasses, with coarse, abrasive leaves. They grow three to four metres high. They produce distinct flowering stems, which stand taller than the leaves. The two pampas species are commonly mistaken for each other and for the closely related native toetoe (also Cortaderia species).

Differences between pampas and native toetoe - flowering characteristics

Pampas		Native toetoe
Common pampas including cultivars 'gold stripe' or 'gold band' C. selloana	Purple pampas C. jubata	C. fulvida, C. richardii, C. toetoe, C. splendens
Flowering time:  February to late May	Flowering time: Late January to mid-March	Flowering time: September to January
Flowerheads: Usually erect and dense. Colour variable - generally white, pinkish or purplish. Flowers with fluffy hairs (female) or hairless.	Flowerheads: Erect, dense and very uniform. Flowering stems mostly purple, fading to dull brown.	Flowerheads: Generally drooping, usually light creamy-yellow.
Height when flowering: Up to six metres	Height when flowering: Up to three metres	Height when flowering: Up to six metres

Differences between pampas and native toetoe - leaf characteristics

Responsibility for control

Total control of pampas is required by occupiers of quarries, railways and roadsides throughout the Waikato region.

No person shall knowingly communicate, release, sell, offer to sell, display in a place where plants are offered for sale or exhibition, propagate or breed pampas.

Landowners/occupiers in the Taupo, South Waikato, Matamata-Piako and Waipa districts, Hamilton city, and parts of the Waikato, Hauraki, Waitomo and Otorohanga districts are required to destroy all pampas on their property.  

How to control pampas

Physical control

• Pampas can inflict nasty cuts, so wear gloves and protective clothing.
• For young plants, the best option is to loosen the soil and pull them out.
• For small infestations, cut the trunk or stems off as close to the ground as possible. Remaining plant matter will act as a mulch and shade out the seed bank. A bulldozer can be used to remove big plants.

Herbicide Control

Herbicides are most effective on pampas during spring and early summer while it is growing strongly. Spraying while the plants are flowering is less effective.

• Plants can be slashed to about 30 centimetres from the ground and the re-growth sprayed.
  
• Large mature clumps may require follow-up control.

• Very dense sites can be sprayed. Total coverage of the plant is required.

Summary of herbicides and application methods for control

When using herbicides:

• read the instructions on the manufacturer’s label closely.
  
• always wear protective clothing.
  
• always minimise the risk to desirable plants.
  
• contact the supplier for further advice.

Management control

After initial control, it’s important to:

• revisit the site at least annually to control re-growth
  
• stop weeds invading by replanting with desirable plants (preferably natives) once re-growth is no longer a problem.

Disposal

Mulch or compost.

More information

For further advice contact your nearest biosecurity pest plant contractor on 0800 BIOSECURITY (0800 246 732).

For more information on what we do phone Environment Waikato's freephone 0800 800 401.

For more information on pest plants check out the Weedbusters website.

Related publications

View our Waikato Regional Pest Management Strategy.

'What makes a pest a pest? - A guide to Waikatos pest management future' download (730 kb, 104 seconds to download, 56k modem) order or pick up for free from our offices.

Pick up or order 'Plant me instead - Plants to use in place of common pest plants' for free from our offices.

Pick up or order the 'National Pest Plant Accord Manual' for $10 from our offices, or view it online for free.

Pick up or order 'Poisonous plants and fungi in New Zealand - A guide for parents, schools and child minders' for $15 from our offices.

Disclaimer

Although this content has been prepared in good faith from a number of sources believed to be reliable, Environment Waikato does not give any warranty that all information contained is accurate or complete, or that advice given will be appropriate in all circumstances. Mention of product trade names implies neither endorsement of those products nor criticisms of similar products not mentioned.