Pampas - the big bully!
A large pampas grass towering over PFK Restoration Adviser Nic
Pampas grass is a really tough pest plant which can bully our native plants, and even us! It can grow into a huge, dense mass of saw-toothed leaves, giving it the common name cutty grass. It can stop people’s access as well as providing habitat for rats and possums! And it’s a fire hazard! It’s long feathery flowerheads produce masses of tiny wind-borne seeds which can float almost anywhere. Read on to find out why it's weedy, how to recognise it and tell it apart from the native toetoe, and find out how to get rid of it.
Why is it weedy?
Pampas grass is very tolerant of a range of environmental conditions.
It can establish quickly after fire or soil disturbance where there is bare soil and increased light levels.
It produces masses of wind-borne seed which can also be spread through soil movement, dumped vegetation, on animals, boots and sometimes water.
It is a fire risk, can harbour rats and possums, and can impede human access. Plus they can be very difficult to remove once they become large.
Upright feathery flowerheads of pampas grass
Pampas forms a large, clump up to 4m and often grows in high light, disturbed areas and outcompetes our native grasses and shrubs, including the native toetoe.
As it spreads through tiny wind-borne seeds, you can make a huge difference by cutting off the flowerheads wherever you can, and disposing of them in your rubbish (or, to avoid seeds spreading further, by pushing the seed head down into the middle of the pampas bush).
How to tell the weed pampas from the native toetoe
Toetoe (a giant tussock grass) of which there are several species plays an important role in New Zealand - some growing on sand dunes, rocky places, while others grow only in swamps, near streams and forest margins.
Toetoe is an important plant for Māori, with the leaves being used for baskets, kites, mats, wall linings and roof thatching. The flower stalks (kākaho) are used for tukutuku panelling, and many parts of the plant have been used in first-aid.
Pampas can be mistaken for the native toetoe but there are some distinctive differences:
Pampas, as they mature, the dead leaves collect at the base in spiral curls, like wood shavings (see image below) - toetoe leaves don’t form these curls.
If it’s flowering in March or April, it’s probably pampas, which flowers from late January. Toetoe usually flowers September to January (although there may still be flowerheads around in autumn).
Pampas flowerheads usually stand upright - toetoe flowerheads bend over.
The leaves of pampas are dull and rough to touch - toetoe leaves are shiny green and smooth.
If you tear crossways across a leaf, pampas is easily torn - toetoe has veins visible between the midrib and margin of leaves (this is a good test as you can use it on young plants).
Curly spirals of dead leaves looking like wood-shavings at base of pampas grass
What can I do to get rid of it?
First, make sure that plant you are looking at isn’t one of our native Toetoe species (use the leaf tear test - see above).
Cut off seed heads and dispose of carefully (e.g. pushed down into the pampas bush, bagged and sent to a transfer station, or deposited in weed composting bag)
Seedlings can be dug out and left on site to rot down providing roots are kept off the ground. Larger plants can be chainsawed or cut down, then roots dug up. Wear thick gloves, long sleeves and eye protection working around pampas because of the sharp-edged leaves.
If you can reach the stem, cut and paste stems with a double strength glyphosate gel such as Bamboo Buster™. Leave cut foliage to rot but dispose of seed heads properly (see above).
Foliage can be sprayed with glyphosate at a 20ml per litre rate, with 1ml of added penetrant per litre. Repeat every 3 months as required until the plant is dead.
Release native seedlings to sprout around it. Or plant natives around it.
*Always read the labels when using herbicides. If working close to waterways or valuable trees, do not use metsulfuron but you can use a glyphosate based herbicide (such as Bamboo Buster™) instead. Use the minimum amount of herbicide, just enough to cover surfaces, and only if rain is not forecast for next 8 hours.
So look out for pampas, check it’s not toetoe, get in touch to report it, and if you can, help to remove it.
Pampas Grass Weedbusters
See page 9 of the Plant me instead booklet
Here are some things you can do to help tackle pest plants in your area:
Recognise - Learn what it looks like
Report - Use our new EcoNet CAMS Weed App to report locations
Remove - Find out how to control the vine and get supplies from our Tool Shed
Restore - Plant natives in its place, to stop it coming back, and to support our native wildlife