Hello Ypoole, Assuming it is a plant like Albo Lacinatus, spring/summer is best. It will be hard work, but advise digging and cutting half of root ball back 6 weeks before you want to shift and then refill soil back in hole. One month later, cut all foliage back to one third and then dig and cut other half of root ball. 2 weeks later remove the lot out of hole and start dividing (with much effort). It is a very hardy plant and will survive.

I'd have to ask, is it worth the effort as it grows easily from cutting and if you want the mass effect, put lots of cutting together.

Good luck and enjoy.

Regards, Brian Kerr.

You can dig it up now in your area, will be hard as they go quite deep. If it is really big you can split with spade or an axe into big chunks, they can take it, that's what I do. Keep as much root on each piece as you can, then plant immediately in well prepared soil.

did cuttings (accidentally broke), and they are growing. I just pull apart the pieces after digging it all up. There are a lot of stem/root pieces all bundled together underground. Do it in late march through mid May, I think is good.