Advice needed on dividing iris'?

Question

Hiya,
I live in Philadelphia (but am not sure which zone I am in in case that's needed) and Last spring a neighbor gave me a few iris' which transplanted with no problems. I planted them in the exact clumps in which they were provided, and they have since bloomed and faded for the season. My questions are as follows:
1.)One clump has tripled in size, can I split this clump to help fill out the bed more? If so, what is the recommended method as I border on having a black thumb?

2.)If I am able to divide, when is the best time to do so (am hoping now as they are done blooming to the best of my knowledge) to minimize the chance of killing the plants?

Thanks a bunch :)

Answer 1

I've been able to divide iris any time the ground isn't frozen, but most experts recommend late summer. Cut the leaves back by half and try to get a thumb sized piece of rhizome with each division or at least a little root. When your done, your going to have pieces of rhizome with no growth points. Just throw them away, they're kind of like the extra pieces you get when you assemble a futon.

Answer 2

If th iris has grown that much it is in a good situation and healthy so division should be possible. It should be done, at a minimum, 8 weeks after bloom. The best time is after the temperatures have cooled in you area but not into the cold of late fall to avoid bacterial soft rot. Temps in the 60 - 70s would be good. Iris are generally divided every 3- 5 years to keep them at full bloom.
I generally cut the leaves down to 1/3 their original length. I go around each clump loosening the soil with a fork or transplant spade. Once free I prefer a Sawz-all to a knife for cutting heavy fibrous roots like Siberian iris have. In the new site I add compost and a handful of bonemeal.

Answer 3

Let me answer the first part of your question first. Don't cut back or divide your iris yet. The leaves are making food for next years' blooms. The best time to divide/transplant iris in our area is around the first of August. Cut back the leaves to about two or three inches. Lift the rhizomes using a lifting fork. Separate the clumps into one or two rhizomes that each have a healthy leaf cluster growing from it. Don't worry if you have to break or cut some of the clumps apart. Check for rot, insect infestations, etc. in the rhizomes. Re-plant about 8 to 10 inches apart, but don't plant them too deeply. You can feed with bone meal and water in well. They should do fine.

Answer 4

U can plant and divide iris anytime in the warm months, just keep them watered until they settle in. They are finished blooming for the season very rare they bloom again. To answer your question, Yes u can split the roots. Good Luck maybe you will have green thumb after all

Answer 5

You need to wait until fall to divide the bulb. That is when plants go dormant in most zones and you will have the best luck doing it. There should be a line where it looks kind of like an absess or extra blub attached and you break in on the crease. Hope this helps I know it was a strange way to describe.

Answer 6

I have divide mine always in the fall, they like to be divide every two yrs they seem to bloom more if you do this, to divide them take a shovel and split them anywhere, but make the clumps big, they are very hardy and will do fine

Answer 7

These folks have an AWESOME "how-to" page:

http://www.schreinersgardens.com/about_iris.shtml

*~Enjoy~*