For the Love of Iris

Articles, Tips and Notes from Schreiner's Iris Gardens

Saving Overgrown Iris

142 Comments

Nature happens....

Nature happens….

Let’s say a friend told you about this patch of once-lovely Iris which has become completely engulfed by grass… (or maybe that friend is you…) You tell your “friend” that her situation reminds you of something you once read by Sara Stein*: “I appreciate the misunderstanding I have had with Nature over my perennial border. I think it is a flower garden; she thinks it is a meadow lacking grass, and tries to correct the error.”

July, August and, in some areas, September, is the time to assess the situation in your Bearded Iris garden, and rectify the misunderstanding you might have with Nature. If it’s been a few years (say three to five) since you planted your Iris, it is likely that the clusters have grown, and over-grown, themselves into a large mass of rhizomes 12 to 24 inches wide. If you are (or know of) that friend described above, fear not. If you see foliage above the blanket of grass, the Iris can be saved! Read on.

Before you reach for the shovel, though, let’s review some tips on dividing and transplanting the new Iris babies.

Iris Identity: If you have your Iris labeled, you will want to label all of its babies. Prepare tags of some sort to help you keep track of what you are transplanting and where. If you haven’t labeled the Iris in your garden, then proceed unfettered by the bondage of labels….

Digging the clumps: Depending on how densely packed the Iris clump is, you may wish to dig up the entire mass and work on it out of the ground. In the case of the clumps overgrown with grass, you’re best bet is to dig up the whole shebang. Carefully pull the soil and grass away from the rhizomes and roots so that you can see what you’re dealing with. Take care to remove as many of the grass roots as possible. Once cleaned up, you will likely find that the mass of Iris resembles a tangle of fresh ginger, or small oblong potatoes, some of which will have fresh green foliage attached.

bearded iris|growing iris

New growth on left and right of spent rhizome

Separating the plants: The rhizomes with the foliage are the plants you will keep. Any rhizome which has no foliage is “spent”, and will not bloom again. It can be discarded. At this point, you can decide how many of these new plants you’d like to replant. Some of the new growth may yet be quite small, the size of a cherry. These are called “nubs”, and will have tiny green leaves. You can plant these, but expect possibly two years at least before you see any blooms.

To separate, carefully snap or slice the rhizomes at the junction between the old plant and the new growth. Take care to disentangle the roots so that the new plants retain their set of roots.

Cut or break off new growth from original rhizome

Cut or break off new growth from original rhizome

If the foliage on the new plant is very tall, you can trim it back to 6 inches to make transplanting easier.

Prepare soil for transplants: For the area where you intend to plant the new growth, dig up the soil 6 to 12 inches deep, remove weed sprouts, mix in some organic mulch or a low-nitrogen fertilizer (follow manufacturer’s recommendations for quantity and ratio) to give the soil a nutritional boost. Break up large clumps of soil and smooth out the area. Plant your new iris so that the roots are covered but the top of the rhizome is showing above the surface of the soil.

Water in: Water at the time of transplanting. Newly set plants need moisture to help their root systems become established. Specific watering requirements depend on your climate and soil, but keep in mind that deep watering at long intervals is better than more frequent, shallow watering. Once established, Iris normally don’t need to be watered except in arid areas. It is always better to underwater than over water. Too much water can induce rot.

What to do if you have more Iris shoots than you know what to do with: Consider donating the extra plants (labeled or unlabeled) to a nursing home, school, or community center in your area. You can also check with your neighbors to see if they’d like any of the offspring.

Getting ready to divide your Iris? Tell us what you do with the extras. We’d love to read your comments.

*Sara Stein, influential advocate for gardening with native plants, and author of “Noah’s Garden: Restoring the Ecology of Our Own Backyards” (Houghton Mifflin, 1993).

Author: Schreiner's Iris Gardens

Dedicated to growing and selling the finest Iris in the world.

142 thoughts on “Saving Overgrown Iris

  1. Mid-Sept here. dug up, divided and cleaned iris from an overgrown, shaded bed. Planted the biggest ones. Is there any way of planting the smaller ones in a container of some kind and sinking the container in my veg garden to over winter in my zone 4, in order to distribute the smaller ones in the spring, when more garden space will be available?

    Like

    • Hello. Excellent work! Regarding the smaller iris rhizomes – the nubs….Yes, planting them in a container will work very well. We do not recommend transplanting them in the spring, however. Wait until next summer or September to transplant from container to garden. Best of luck!

      Like

  2. My irises are over grown. Can I thin them in
    August 1, having landscaping cloth layed down with barkdusk. Or do I have to wait until spring. I don’t want to destroy my beautiful
    Iris’s

    Like

  3. How long can you keep iris rhizomes after dividing them before re-planting? What are the best conditions for storing the rhizomes long-term (say 2 to 4 weeks), if you should even do this? Thank you.

    Like

    • Hello. Excellent question! Yes, you may store rhizomes out of the ground for as much as 6 weeks in a cool, dry location, prior to replanting. The stored rhizomes will begin to look dried out, shriveled, with brown, papery foliage. Not to worry. Simply plant as directed and water in well with a dose of low-Nitrogen fertilizer. Give them a good long drink once every 10 days if no rain is in the forecast.

      Like

  4. Thank you for all of the info & beautiful irises. I have a question about rescuing & regrowing irises from old beds. My sister-in-law was very kind to give me a bunch of mystery-colored rhizomes she had originally planted at her cabin in the 1990s. We dug, clipped, sorted, soaked & replanted. Good news, the biggest rhizomes bloomed in two new beds for the last two years. I kept most of the smaller pieces for my tiny side yard, not knowing if I would have mostly miniatures or dwarf flowers vs just immature plants that need more time to develop flowers. What is the lifecycle of “child” rhizomes & how long to they need to grow before producing flowers? Is it possible I ended up with old bits & pieces that are too tired to bloom? The leaves still look great, just a lot smaller than my existing irises (original to my house & over 20 years old) nearby.

    Liked by 1 person

    • Hello, perhaps this is the same comment/question submitted on our other post. Here is the reply again, just to cover all the bases: It sounds like you have a few immature plants which need an additional year or two in order to reach maturity to produce bloom stalks. A good indicator is the foliage. If the leaves are healthy, and the plant is receiving sufficient nutrients and sun, then keep them where they are for another year. Fertilize a month after bloom season with a low-Nitrogen fertilizer (which would be around the end of June), and again in the spring (about the time tulips are blooming). Give sufficient water during especially dry periods. Best of luck! Stay in touch.

      Liked by 1 person

      • Thank you for your quick response! I really hoped this year would reveal treasure! I will fertilize the irises in a couple of weeks & wait to see what colors pop up in 2020+ 🦋 Thanks again for posting all the detailed pictures of healthy rhizomes & directions on how to save them from being buried in the grass.

        Like

      • You’re very welcome. Happy summer!

        Like

  5. unsure what to do, new home, now May 10th almost entire backyard has iris growing everywhere mixed in with tall grass. Dig all now? cut all and wait until September? leave all? Ugh. What to do right now? I have no idea what varieties are here.

    Liked by 1 person

    • Hello! Indeed, a classic situation with iris that have suffered neglect over the years. Not to worry. Wait out the spring, leave the iris foliage intact. Come the summer months, when it is convenient for your schedule and cool enough to work, dig out the entire area. Remove the spent rhizomes, remove grass roots from the iris rhizomes (as per our illustrations in our blog post “Saving Overgrown Iris”), prepare the iris bed with nutritious soil (avoid any packaged soil that is high in Nitrogen), and replant iris rhizomes 12 to 18 inches apart, water in well. Whether you keep a small iris bed, or go big with an expansive spread, next spring should be lovely! Best of luck. Let us know if we can be of further assistance. Visit our “How to Grow Iris” pages on our website for more useful information. Happy Bloom Season!

      Liked by 1 person

    • Hard to say, but removing the grass and dead leaves/ etc from around them can never hurt, and can give you some idea of what you have. Congratulations on your new home!

      Like

      • Love and enjoy the blooms now❤️ Cut tall stems and a few leaves for extravagant bouquets. You will need to dead head daily, but it’s easy. Just snap off the wilted blooms each morning and you will have the most beautiful garden of your life! After your blooming season is over, you can divide the rhizomes and share with your neighbors. You will also find real botanical advice in your library garden books. Enjoy ‼️

        On Wed, May 15, 2019 at 1:07 PM For the Love of Iris wrote:

        > Chrystal Hays commented: “Hard to say, but removing the grass and dead > leaves/ etc from around them can never hurt, and can give you some idea of > what you have. Congratulations on your new home!” >

        Liked by 1 person

      • Thank you for sharing the information! Happy bloom season!

        Like

  6. Well I found this info a bit late. I have aleady dug up my Iris. Should I plant right away or may wait until fall.

    Like

    • Hello Donna. Iris are resilient. Replant the iris now which you have removed. Give them a dose of low-Nitrogen fertilizer (6-10-10 or 5-10-10), water in well. You might have reduced bloom next spring, but we are confident that the iris will survive and thrive. They might surprise you with fantastic bloom next spring! Let us know if we can be of further assistance. Happy bloom season!

      Liked by 1 person

      • How to plant new transplant.? In a group of fans 12″ apart or just a single fan 12 to 18 ” apart?? Help!!

        Like

      • Hello. Yes, we recommend planting iris 12 to 18 inches apart. Each rhizome in a group should be planted as such. In other words, when planting a group of 3 rhizomes, each plant should be 12 to 18 inches apart. Let us know if we can be of further assistance.

        Like

  7. Dear Church Family

    Meet me in the parking lot after Church to receive some of my famous Iris. It’s time to
    divide and share. Remember the 84 blooms in
    In my front yard last summer? They propagated!! I dug up a trunkful this weekend just for you. Even more Bearded Iris in deep blues and purples are still on my yard. Please help spread the JOY!
    Sandi
    PS I am available for Q and A. Iris are easy to grow in our coastal community.

    Like

  8. I live in New Zealand, can I join your site? I have found questions and responses very interesting.

    Liked by 1 person

Share Comments & Questions

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.