In the autumn, so now, really, making sure you have good sections to transplant. They may 'sulk' and refuse to flower next year as they don't like being moved.

thank for your prompt reply ! I moved it about 6 years ago and has flowered ever since but not this year there was plenty of foliage though ,do you think dividing would help ?

It's possible, but I do know that they really don't appreciate being moved.... The general advice, too, is not to plant them too deep, I understand.

Good luck with it!

Pretty much covered there by Spritz. Its possible that a dry spell last year may have stopped the production of the following seasons buds. Re-plant the two sections with plenty of compost worked into the soil. Also add a little bonemeal as this has phosphates that will help in root development. After a few more months, it breaks down even further and starts to release nitrogen for an extra boost. The cut surfaces of the rhizome/rootstock will callus over and seal themselves all the faster because of this feed.

thank you both for your advice i love this site everyone is so helpful

I definitely agree with you there, Lemondrop! I ask questions too - and get good answers. :-)))