Taranaki Regional Council is reminding land owners that they must destroy all pampas on their property. Both common pampas and purple pampas are classed as "eradication pest plants" in the council's Pest Plant Management Strategy.
They suppress native plant growth, threaten horticulture production and can be a nuisance on roadside verges, the council says.
Pampas is a South American grass, from the northern Andes. There are two species, one with flowers that can be pink or purple as well as cream coloured or white.
It was introduced as an ornamental plant, and for grazing and shelter. It is also a pest plant in California, Hawaii and parts of Australia.
Toetoe and pampas look similar and are related species. Both have leaves with edges sharp enough to cut skin. But there are differences.
Pampas flowers are fluffier and more erect.
They appear in autumn, whereas toetoe's droopier and wispier flower heads are out in late spring and early summer.
Their leaves are subtly different. Both are long and grass-like but pampas has a single midrib and its leaves are easily torn in half. When they are dry they dangle in spirals.
Toetoe has a lot of secondary veins in its leaves, which are not easy to rip in half.
