Probably just a cultivated one (Poaceae)

[MWP admin]

Are these just cultivated, imported poaceae or they can be found naturalized in the wild?

The plant was some 2-3m high

[RB]

Think it's called "pampas grass" and very definitely non native.

I have a clump of this, in summer it appreciates a little bit of water or else it goes a bit ugly, like mine did.

RB

[MWP admin]

Pampas grass (Cortaderia selloana) is a large perennial grass native to Brazil ..

http://www.blueplanetbiomes.org/pampas_grass.htm.

Thanks

[Sdravko]

yep

[Danpav]

Be vigilant
It's an invasive species !