Should I divide iris now?

Hi all, as a newbie to this gardening lark I need a bit of help with what to do with an iris.

It was in the garden when we moved in and looks like it's been there a while as it's a rather large clump. It did flower this year, just about managed two flower spikes which were over and done with in less than a week

So I read somewhere that they should be dug up and divided when they become congested, which I figure this one is, but I am ok to do it now? Because I also read that if done at the wrong time of year the roots will rot before having a chance to grow??

Also how big should the bits I divide it into be? and should I replant them all or just keep the bit that flowered? So many questions! Any advice really appreciated

 

You can do it now. But I would not cut the leaves in half, all the leaves are there for energy to feed the bulbs. It will cause more stress to cut them. Make sure you plant them the same depth from which they are from.

 

Can i hijack? Was just wondering...if I wanted to take some iris from my parents garden, would now be a good time to do it ... Just like seperating except some get planted in my garden?

 

When to transplant does depend on which Iris you are talking about. There are 2 different types - the bulbous iris and the rhizome iris.
When iris become congested it is a good sign that they do need to be split as it can be the cause of fewer flowers.
Rhizomes - best time for transplanting these is in the summer up to autumn after they have finished flowering. Dig up the clump intact, clean the soil off the rhizomes and divide each into 7-10 cm length pieces, leaving the roots on. You also need to leave a few leaves on them.
Bulbous - these can be transplanted after the foliage has died down.