That's sedge, whatever you do to that you're unlikely to kill it. Also, you'll have seedlings coming up for ever, so you won't run out of it...

That sedge is carex pendula and a right thug it is. I was advised not to plant it and planted it anyway, but have had to dig it out and dispose of it as it seeded absolutely everywhere as Teadrinker says, including my containers. Honestly I would leave it and get something similar. I've seen several at Kew the same height but sadly don't know the names.

I agree it is a thug - seeded itself all over my gravel paths and it took two applications of Glyphosate to kill it. Can I suggest Miscanthus zebrinus about the same height and so far after three years very well behaved does not seed itself around or send out runners.

Nice one Wendy. Do you know of a tall one that gracefully bends over at the top with a similar effect to the Carex?

Hi Steragram - any that I have had with that kind of habit have ended up being turfed out as they all seem to be of the Carex variety and all seed around. Maybe someone else has tried one that doesn't

I know it is widely reported that it seeds everywhere but I've had one for about five years and it hasn't self-seeded anywhere (yet) even though I have a lot of gravel and about thirty pots. The borders are clay and nothing wants to seed there. The Carex Pendula is so graceful and the only problem I have is that it is now too wide and smothering other plants so I need to split it and move it.