Cortaderia selloana
NPPA pest plant
Environmental Weed (2024)
Common names
pampas grass
Family
Poaceae
Flora category
Vascular – Exotic
Structural class
Grasses
NVS code
The National Vegetation Survey (NVS) Databank is a physical archive and electronic databank containing records of over 94,000 vegetation survey plots - including data from over 19,000 permanent plots. NVS maintains a standard set of species code abbreviations that correspond to standard scientific plant names from the Ngä Tipu o Aotearoa - New Zealand Plants database.
CORSEL
Conservation status
Not applicable
Simplified description
Robust tussock with tall erect flowering stems bearing dense heads of white to pale pink flowers.
Habitat
Terrestrial. A coastal and lowland plant found between sea level and 800 metres. Plant grows in sites of all levels of fertility from low to high. The plant grows in a wide variety of soils from pumice and coastal sands to heavy clay (Ford 1993). Coloniser of open ground (West, 1996). A plant that occurs in low or disturbed forest (including plantations), wetlands, grasslands, scrub, cliffs, coastlines, islands, forest margins, riverbanks, shrubland, open areas, roadsides and sand dunes. The plant’s primary habitat is disturbed ground.
Wetland plant indicator status rating
Information derived from the revised national wetland plant list prepared to assist councils in delineating and monitoring wetlands (Clarkson et al., 2021 Manaaki Whenua – Landcare Research Contract Report LC3975 for Hawke’s Bay Regional Council). The national plant list categorises plants by the extent to which they are found in wetlands and not ‘drylands’. The indicator status ratings are OBL (obligate wetland), FACW (facultative wetland), FAC (facultative), FACU (facultative upland), and UPL (obligate upland). If you have suggestions for the Wetland Indicator Status Rating, please contact: [Enable JavaScript to view protected content]
FAC: Facultative
Commonly occurs as either a hydrophyte or non-hydrophyte (non-wetlands).
Detailed description
Large-clump-forming grass to 4 m+. Leaf base smooth or sparsely hairy, no white waxy surface (cf. toetoe—Austroderia—species). Leaves with conspicuous midrib which does not continue into leaf base, no secondary veins between midrib and leaf edge; bluish-green above, dark green below, snap across readily when folded and tugged (toetoe species have multiple ribs in the leaves, making the leaves difficult to snap across). Dead leaf bases spiral like wood shavings, which makes pampas grasses more flammable than toetoe species. Flower head erect, dense, fluffy, white-pinkish, fading to dirty white.
Similar taxa
Can be separated from native Austroderia (toetoe) by the prominent single midrib on the leaves (Austroderia species have several prominent veins.). Can be separated from C. jubata by the glabrous leaf bases, and the fresh flowering spike is white to pink rather than violet of C. jubata, and is exerted further from the clump.
Flowering
March–May
Flower colours
Red/Pink, White
Fruiting
April–May (Timmins & MacKenzie 1995).
Life cycle
Perennial. Seed germination occurs in autumn.The plant is dioecious with 50% female and 50% hermaphrodite plants. The plant is readily cultivated from divisions. Seed production is from 90 000 – 100 000 per seed head. It is unlikely that this plant forms a long term seed bank. Viability in the seed bank is unknown.
Seed is dispersed by gravity, man, vertebrates, machinery, in gravel (Timmins & MacKenzie 1995) and by wind. The seed is very light and is wind-dispersed up to 50 km.
Year naturalised
1925
Origin
Central South America
Reason for introduction
Agricultural.
Tolerances
Seedlings are intolerant to drought and slightly tolerant of frost. Seedlings are slightly intolerant to intolerant of poor drainage. Adult plants are tolerant of drought and frost. Cutting results in regrowth. Grazing results in regrowth unless it is frequent, which results in death. Burning results in vegetative regrowth and provides a seedbed for invasion from surrounding areas.
National Pest Plant Accord species
This plant is listed in the 2020 National Pest Plant Accord. The National Pest Plant Accord (NPPA) is an agreement to prevent the sale and/or distribution of specified pest plants where either formal or casual horticultural trade is the most significant way of spreading the plant in New Zealand. For up to date information and an electronic copy of the 2020 Pest Plant Accord manual (including plant information and images) visit the MPI website.
Environmental Weed (2024)
This plant is named in a list of 386 environmental weeds in New Zealand 2024 prepared by DOC. 759 candidate species were considered for inclusion on this new comprehensive list of environmental weeds in New Zealand. The species considered were drawn from published lists of weed species, lists of plants that must be reported or managed by law if observed, existing national and regional programmes and agreements for pest management, and species already managed by the Department of Conservation (DOC). Candidate species were then assessed to see if they were fully naturalised and whether they have more than minor impacts in natural ecosystems. Read the full report here.
References and further reading
Timmins SM, Mackenzie IW. 1995. Weeds in New Zealand Protected Natural Areas database. Department of Conservation Technical Series 8. Department of Conservation, Wellington, NZ. 282 p.