Posted: 20/10/2014 at 17:36
I do mine about once a year.
Just empty the pot and remove corms/rhizomes.Let soil dry out a bit as this makes it a bit easier.
Refill pot to about halfway with fresh compost,put the best corms on the surface and then fill to the top with more compost.Water and wait.It will not be long before shoots reappear.
Sometimes while it is growing and it looks 'weedy' I cut off all the foliage (haircut!) and wait for new leaves to grow,top up with fresh compost if needed.
Some years ago I put all the old soil and corms in the compost bin.Even today I still have plants growing all over the garden from corms that stayed viable in the compost bin!!!