Anyone know?

J52 these have never flowered to my knowledge ( I don’t even know where they ve come from or when) just remember seeing the pot full of greenery for the last few years there really was dozens and dozens in fact I ve got a big old pile perhaps I ll put them in the garden where they ve got more room to spread if they want to and see what happens

I don’t think they have to be frost-free, J52. I have a big clump that has been undisturbed for the last 20 years in my cold clay-soil garden & flowers every year.
Maybe some varieties are less hardy?

If they are, they do best by being overcrowded in the pot! It put them back in the same pot with new compost and put in a frost free corner.

What j52 said.

Could be Agapanthus.