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How to Divide Iris Rhizomes

Dividing Iris is easy and is a great way to get more to share. It also keeps your Iris healthy for great blooms! Here is an easy how to divide Iris Rhizomes step by step with video.

In this post I share how to divide Iris rhizomes, an easy step by step photo demonstration. There is a video at the end of this post where I take you through it too.

Iris are such a fun plant and so rewarding.  Have you planted some and now they have started to not produce as many blooms as in past years?  Iris usually need to be divided once every 3 years or so.  That is not a hard and fast rule but a generalized observation for most.

I can start in August and continue on through September. Since I have so many Iris rhizomes that need dividing, spacing out the actual work makes it less of an arduous chore. 

Iris with wording, How to Divide Iris step by step

I live in the Sierra Nevada mountains of N. California at the 4500 foot level.
We get plenty of winter snow and cold, then some mighty fine summer weather averaging in the 80’s to low 90’s.

We are considered a Zone 7 (we have now been upgraded to Zone 8).
I have gardened with Iris for 35 years now.
Here and in the San Joaquin valley.

When to divide Iris Rhizomes

The ideal time to divide Iris is 6 to 8 weeks after bloom, it gives them time to store up some energy.

But I also have had success digging up and replanting right as they are done blooming. I do better in remembering what color is where, I always say I am going to mark them while blooming and somehow never get around to it.

I have started to video during the blooming season so I can refer to the video to see what color is where.  It works wonderfully!

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This clump of Iris is done for the season. Some varieties will bloom again if you dead head, they are called reblooming Iris and it will be noted with the rhizome when you order or buy them. They really do rebloom and it is usually in September in my neck of the woods. 

If you want to know what deadheading is then see this post, Dead heading for more blooms

Some people tidy the plant after blooming by shearing off the leaves, but I don’t. And here’s why….

The rhizomes are fed by the leaves and it is better to let them remain to soak up the summer sunshine and build up a food store for next years blooms. When the leaves yellow or look otherwise damaged you can shear those off but leave the healthy looking leaves to provide the food for the rhizome to store. 

You will have bigger and healthier flowers next year. 

how I separate my iris or divide iris

Cure & Store Iris Rhizomes

If I am going to store or cure the rhizomes to give away I prepare a container with a bit of straw to lay them in. The straw allows air to circulate around the rhizomes which discourages rot. I also just lay them out on the ground or on our deck to dry.  We live in a low humidity area so this is sufficient.

Some dust the rhizomes with sulfur or a powdered anti-fungal. I have not had to do that but you may need to consider it if fungus is an issue in your area. 

how I separate my iris, how to divide iris rhizomes

Dig up Iris Rhizomes

Start a good 5 to 6 inches back from the base of the Iris clump and dig in your shovel or garden fork.  Loosen around the clump as best you can.  It is easier on your back. 

how I separate my iris, how to divide iris rhizomes

Iris are not planted deep, they should be very near the surface but their roots can long. In the video attached you will see I really have to put some muscle into digging around the clump I am dividing.

how I separate my iris, how to divide iris rhizomes

Again, work around the entire clump to loosen it from the dirt. Once you have it well loosened it should pull up very easily. 

how I separate my iris, how to divide iris rhizomes

You can merely shake off the dirt or hose off the excess dirt to inspect the rhizomes for rot or insect damage.

The roots can by quite long and I trim them back for easier replanting. I grab the roots at the base of the rhizome and cut what hangs below my fist. Then I trim back the leaves to about 6 inches long.

Sometimes rhizomes will separate themselves from the clumps voluntarily but usually I need to cut them apart.

how I separate my iris, how to divide iris rhizomes

Separate Iris Rhizomes

To separate and/or cut out diseased and old gnarly bits, use a clean sharp garden knife and cut it off at the joint.

how I separate my iris, how to divide iris rhizomes

It is easy to see where the joint is on this one, the rhizome narrows. (see example above)

how I separate my iris, how to divide iris rhizomes

It is highly recommended to thoroughly sanitize your cutting tools between cuts so you do not spread disease. Wiping them well with rubbing alcohol works fine for me. Just make sure it is dry before cutting more.

I have never had an issue with disease so you don’t see me cleaning between cuts.

how I separate my iris, how to divide iris rhizomes

I started to use the basket with straw but had way too many rhizomes so I laid most of the out on the shady porch to dry.

Planting Iris Rhizomes

If you are not giving the extra Iris rhizomes away you can replant immediately, click here to see how I replant.

I will print a photo of the Iris in bloom and place it with the rhizomes I am giving away so whomever I gift it too will know what color it is.

If I am replanting in my garden I keep a hand drawn garden map of where I have put things. This past summer I kept a video garden journal and that has been excellent and helping me see what is where at any particular time of the growing season.

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I wish you great success with your Iris, they are one of my favorites and they are so easy!

Want a downloadable checklist?  It is available in the Printable Library.  Your password is at the bottom of the last email I sent you. 

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pink and lavender iris with text overlyay, Easily divide Iris for many more, Flower Patch Farmhouse

Happy Gardening!

More You Will Enjoy!

Visit to an Iris Farm
How to Divide Iris in Spring
Growing Iris for Loads of Blooms

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Rebecca Payne

Sunday 25th of October 2020

I love all your tips and beautiful photo's.

isabelle

Sunday 9th of August 2020

has anyone ever tried dividing irises without digging them up? I have several beds about 5 ft wide that I have not touched in years. They are beautiful, although maybe there would be even more blooms if they were not so crowded (some rhizomes on top of others). Could I take a cutter, just cut off 2 out of 3 irises and pull them off gently. seems easier than digging, lifting, separating and then planting. What do you think?

Pamela

Monday 10th of August 2020

Having done it both ways myself I wouldn't say it is easier, just different. See this article: How to Divide Iris in Spring

isabelle

Sunday 9th of August 2020

My iris have not been touched in 15 years. In the past I dug, separated and replanted but I was wondering: instead of digging them, since the clumps are 4 ft wide and tangled, can I go in there with a cutter and get rid of all the old rhizomes; or even get rid of new rhizomes so the remaining plants are well spaced? has anyone tried that?

Pamela

Monday 10th of August 2020

Yes, I have an here is the article where I show how I do it. How to Divide Iris in Spring and still get Blooms

Ellen Barnett

Monday 8th of June 2020

I watched a video by Manitoba master gardener, and she said to throw away the rizome that just bloomed because it won't bloom again. Thoughts? I replanted a bunch last year, and they look healthy but most did not bloom. --Ellen

Pamela

Monday 8th of June 2020

Yes, you can see the one that I throw away in the photos of this post, it is noticeably shriveled up.

Tammy

Saturday 2nd of May 2020

I am so glad I came across your post! I inherited my Iris's from the former homeowners. Your instructions will be very handy!

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