Hello its called molinia, common name [moor grass] and is a perrenial, looks great tucked into an herbacious border, julien.

Looks more like Phalaris arundinacea aka gardener's garters.

I've viewed images of Molinia and am not convinced ... sorry Julien!

Wagger ... off to view Phalaris next ... I'll be back!

Definitely Gardener's Gaiters. An absolute thug if suited.

Yep, I've looked at a fair few images of this on member's pics and certain it IS Phalarus. My thanks to both Wagger and Owdboggy. It's not spread very much in two years, but I did notice it growing through a small Hydrangea today. I'll be uprooting that part at the weekend!

thanks for the ID. Total coincidence that I photographed mine today & wondered what it was. It started off as the smallest piece which I transplanted last year (from original occupants ) & have to say it has grown incredibly fast. Very nice clump but one to keep an eye on I suspect. Will put a photo up now.

Ooh, that's odd isn't it? Just viewed the pic of yours and mine seems paler? Are there lots of varieties?

Hello Shirley, I used to have this in one part of one of our borders, but when it popped up about 12 ft away from the main plant, I knew it was trouble! So, reluctantly, I methodically went through the border and took it all out. It's a pity, because it was a lovely plant...just badly behaved!

I have just dug mine out too, and I keep finding it popping up as Libet says!!! If you contain it then enjoy it but beware.

I've offered some to a member ... will send PM asking her to view your comments! Thanks all. : o ))