T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network

Cortaderia selloana & Cortaderia jubata (Pampas grass)

Kingdom: Plantae
(unranked): Angiosperms
(unranked): Monocots
(unranked): Commelinids
Order: Poales
Family: Poaceae
Genus: Cortaderia
Species: C. selloana and C. jubata
Botanical name: Cortaderia jubata (purple pampas)
                          Cortaderia selloana (white to pink pampus)
Common name: Pampas grass, Cutty grass

Pampas Grass is a tall grass native to southern America forming large clumps growing up to 4m. Leaves are dark green with leaf base hairy for purple pampas and sparsely hairy for C. selloana. 
Leaves snap readily when tugged. 
Dead leaf bases spiral like wood shavings.
Flower-head erect, dense and fluffy. C.jubata bright purple fading to dirty brown, C.selloana white-pinkish fading to dirty white.
Pampas grass is a problem because is tolerant of a wide range of growing conditions. It seeds prolifically and is widely dispersed by wind, water, contaminated soil etc. It displaces groundcovers, shrubs, and ferns, creates fire hazards and provides habitats for rodents and possums.

For detail information on Pampus grass visit http://www.weedbusters.co.nz/weed-information/cortaderia-selloana/59/

Pampas grass looks quite similar to Cortaderia richardii (Toetoe) a New Zealand native grass.  

An area infested with Cortaderia selloana

Thanks to Wikipedia for text and information: https://creativecommons.org/licenses/by-sa/3.0/