Pampas
Botanical Name
Cortaderia selloana
Family
Poaceae (grass)
Also known as
Cutty grass, Prince-of-Wales feathers
Where is it originally from?
South America
What does it look like?
Large-clump-forming grass (<4 m+). Leaf base is smooth or sparsely hairy, with no white waxy surface. Leaves are blueish-green above and dark green below, have a conspicuous midrib which does not continue into leaf base, no secondary veins between midrib and leaf edge, and snap readily when tugged. Dead leaf bases spiral like wood shavings. Erect, dense, fluffy, white-pinkish flowerheads (Jan-Jun) fade to a dirty white as seed forms.
Are there any similar species?
C. jubata and native Austroderia species (toetoe) are similar. Toetoe leaves don't snap readily, midrib continues into leaf base, have distinct secondary veins between midrib and edge, and white waxy leaf sheaths. Dead leaves don't spiral. Drooping, light golden-yellow flowerheads (Sep-Jan).
Why is it weedy?
Tolerates heat and frost, salt, wind, wet and drought, moderate-shade, most soils, low fertility, and recovers quickly after fire. Massive amounts of well dispersed seed are produced.
How does it spread?
Seeds are spread very long distances by wind and occasionally water. Seeds are also spread by soil movement, dumped vegetation, contaminated forestry machinery, clothing, and on animal pelts. Common seed sources are plantation forests, roadsides, farm hedges, quarries, and wasteland.
What damage does it do?
Colonises sprayed, burnt, slipped and otherwise disturbed sites and quickly becomes dense. Replaces groundcovers, shrubs, and ferns, creates fire hazards, provides habitats for possums and rats, and impedes access. Normally followed by weedy vines.
Which habitats is it likely to invade?
Forest light gaps, slips, margins, disturbed sites, open habitats, riverbeds, cliffs, inshore and offshore islands, tussockland, fernland, herbfield, duneland, coastline, gumlands, salt marsh, estuaries, and shrublands.
What can I do to get rid of it?
Establish that the species is not toetoe (look for erect seed heads in autumn)
1. Physical control: Dig or grub out seedlings or small plants. Chainsaw small plants and remove sizeable plants by bulldozer. Compost or leave on site to rot down. Burn or bury any flowerheads.
2. Spray: 520g/L haloxyfop-P-methyl (150ml/10l + crop oil) for most sites or glyphosate (100ml/10L + penetrant) for very dense sites. Use a marker dye to avoid wastage and a foaming agent to help prevent spray drift. Leave the plants in the ground until the roots have died off.
What can I do to stop it coming back?
Seed banks reinfest bared, burnt and sprayed sites, and grazed plants resprout. Plan for increased fire risk after control. Pampas recedes as shade increases, so encourage weed replacement (planting, regeneration) as you carry out control. Follow up as needed, but do not reapply herbicide too soon after the initial treatment - wait until the plant actively begins growing again.
