name?

I think it's a weed Irish, sorry. There was a clump of it in my friend's garden and I tried to get rid of it for her a few weeks ago. It was quite tough to dig up.
It probably came to your garden via some bird or something. I'd evict it a s a p before it spreads.

it usually grows near water - It grows on the stream bank where I planted recently, but I have left it in as it adds a bit of interest and the roots, being strong, are helping to bind the bank together. In a pot? Probably a nuisance. I'd agree with Blodyn - remove it!

thanks , its been in this container for quiet a while now, prob over a yr, i left it as it looks interesting.

I bought one for my pond years ago and now it pop's up here and there, I dont mind as I transplant it to where thing's dont grow well. Jackie x

thanks jackie, i think ill leave it where it is for the time being, it hasnt spread its self anywhere in the garden , no yet anyway, and it does add interest in the container

Think it's called a Junca or Juncus? ie sedge

yep sid its juncus, i googled it, thanks