Geranium 'unknown'

I don't think it's a geranium. It looks like an astrantia to me. lol

Thanks Hywel! Andrewr agrees with you on the close up pic! I was told when I bought it it was an alpine Geranium.
Can you tell me, will I need to move it to a larger container?

It grows into a large clump. It will need quite a large pot eventually. It's very hardy. I have them in the ground and just leave them there. There are different shades aswell. They preffer some shade/moist conditions.

Thanks Hywel....I have been to look at it and the base of the clump already seems bigger than when I took this picture! I assume it would be better to move it after the growing season? But in the meantime I don't want it to smother my alpines!....?

If it's smothering things you could move it now. Plant it in a large pot and give plenty of water. It likes shade so it will probably be allright. I'd cut some of the leaves off if you disturbe the roots though. It's quite a tough thing so I would say move it.