Getting Rid Of This

Hi,
See photos I understand this is Carex Pendula, Pendulous Sedge. This has been growing in my garden and spreads quite quickly. Did lever a fork to get a bit up, quite hard going, roots seem strong and pretty deep I also hurt my foot trying to get it out. I'm thinking I'd use a weedkiller on it. If I pour solution into the middle of each clump early morning or at dusk, will it spread throughout the whole clump?
When it dies off I think it would be easier to dig out and avoid hurting my foot. Which weedkiller would be most effective?
Thanks.

 

@Pollys13

and self seeds if given a chance, makes a good present for those you don't like.
I would have thought glyphosate would shift get one formulated for tough weeds.