I love bearded irises. I must, because somewhere along the way I ended up with more than 500 of them growing throughout our half-acre gardens. In spring, when they're blooming and the yard is filled with color, having 500 irises seems like a wonderful idea. Come summer, when I'm standing outside with a garden fork looking at all the clumps that need dividing, I occasionally question my enthusiasm.
That's the thing about bearded irises. You plant them, they settle into the garden, and before you know it those nice little groups have become rather large families. The rhizomes multiply, the clumps spread and eventually everybody seems to be sitting on top of everybody else. When that happens, I know it's time to divide them.
I've found that dividing my established clumps every three or four years keeps the iris beds manageable and gives me a chance to see what's really happening underneath all that foliage. I can remove damaged rhizomes, check for iris borers and give the plants some breathing room before the whole process begins again. And with more than 500 irises, believe me, there is always a clump somewhere in the garden that needs attention.
Dividing bearded irises gives overcrowded plants room to grow and bloom again.
How I Know My Irises Need Dividing
I don't really need a calendar to tell me when an iris clump has become overcrowded. The plants usually make it fairly obvious. The rhizomes begin running into and over one another, flowering isn't quite what it used to be, the center of an older clump may begin looking tired, or the irises simply wander considerably farther than I remember giving them permission to go.
That's about the time I get out the garden fork. I've learned not to put the job off for too long because a crowded clump that looks manageable one summer apparently spends the winter plotting against me. By the following year, it can become an enormous clump that makes me wonder why I didn't deal with it when I had the chance.
Irises Growing Throughout My Garden
All of the irises shown in these photographs are growing in my own gardens. There are plants tucked into different beds throughout our half-acre property, and over the years they have multiplied considerably.
Bearded irises growing in my garden.
One advantage to seeing the same plants year after year is that you begin to recognize when something has changed. I know what my established clumps normally look like, how well they usually flower and approximately how much space they occupied before they began making their own decisions about property boundaries.
One of the bearded irises blooming in my garden.
The blooming season is, of course, the glamorous part of growing irises. Once the flowers are finished and summer arrives, the reality of having hundreds of them becomes a little more obvious. Somehow nobody ever takes a lovely garden photograph of me standing in the summer heat covered in dirt with a shovel in one hand and an enormous pile of iris rhizomes at my feet.
When I Divide My Bearded Irises
I generally divide established clumps every three or four years, although I pay more attention to the plants than I do to the calendar. If a clump is becoming badly overcrowded or isn't flowering as well as it once did, there's no particular advantage to making it wait another season just because it hasn't reached its official dividing anniversary.
I usually tackle the job during summer after flowering has finished. I also don't try to divide hundreds of irises in one heroic weekend. Some beds need attention before others, so I work my way through the areas that actually need it. I've learned that looking across half an acre and thinking about how many irises are left to divide isn't particularly good for morale. It's much better to concentrate on the clump in front of me.
Lifting an Overgrown Iris Clump
When it's time to divide a clump, I use a garden fork or spade and carefully work around it. I'm trying to lift the rhizomes and roots rather than chop everything apart before I've even had a chance to see what is there.
Once the clump comes out of the soil, things get interesting. What looked like one respectable iris plant above ground can turn out to be an entire underground neighborhood. I shake away the loose soil and, when necessary, rinse the rhizomes so I can get a good look at them.
This is when I sometimes wonder how dividing an overcrowded plant is supposed to solve my problem. I started with one clump, and now I'm sitting there looking at enough healthy pieces to start another iris bed. Apparently the solution to having too many irises is frequently more irises.
Choosing Which Rhizomes to Keep
I don't replant everything simply because it came out of my garden. I'm looking for firm, healthy rhizomes with good roots and healthy foliage. Old, soft or badly damaged sections aren't something I want to put right back into the bed after going to all the trouble of digging everything up.
Healthy younger rhizomes can be separated from the older portions of the clump. If they come apart easily, that's wonderful. If they need to be cut, I use a clean, sharp knife. After dividing them, I trim back the foliage before replanting, which makes the divisions much easier to handle when I have quite a few sitting beside me waiting for their turn.
And "quite a few" is a dangerous phrase when you grow hundreds of irises. One large clump can suddenly produce a surprising number of perfectly good divisions, and throwing away a healthy iris is much harder than convincing yourself that surely there must be one more empty spot somewhere in the garden.
Checking for Iris Borers and Rot
Dividing is also the perfect opportunity for me to inspect the rhizomes closely. I look for anything that doesn't seem right, including soft or mushy areas, obvious damage, tunneling or signs that something has been enjoying my irises considerably more than I have.
If a rhizome is badly damaged or rotten, I discard it. I've learned there's no point carefully replanting a problem simply because I hate throwing away a plant. If damage is small and localized, I can remove the affected portion with a clean, sharp knife, and I keep my cutting tools clean as I work so I'm not carrying a problem from one plant to another.
With more than 500 irises, I already have plenty to grow. I don't need to cultivate diseases too.
Keeping My Iris Beds Clean
I also try to keep old foliage and debris cleaned out of the iris beds. Garden cleanup may not be the most exciting part of growing flowers, but when you're dealing with large plantings, letting old material accumulate can eventually turn a small job into a much bigger one.
I don't think I've ever walked outside on a beautiful morning and thought, What a wonderful day to clean up dead iris foliage. Still, experience has taught me that keeping up with these little jobs is much easier than letting everything pile up and dealing with it all at once later.
That's probably true of most gardening chores. We know what we should do, we occasionally decide it can wait, and then the garden eventually reminds us why it shouldn't have.
Sun and Soil for Bearded Irises
My bearded irises bloom best where they receive plenty of sunshine, so good light is one of the first things I consider when deciding where to put a new division. I also pay close attention to drainage because bearded iris rhizomes aren't something I want sitting in soggy soil.
If water regularly collects in a particular area after rain, I would rather find another location for the irises than spend the next several years trying to convince them to enjoy a place they clearly do not like. I've learned over the years that sometimes the simplest gardening advice is also the best: if a plant keeps telling you it doesn't like a location, believe it.
One of the yellow bearded irises growing in my garden.
Good soil, plenty of sunshine and good drainage aren't terribly exciting instructions, but when the plants bloom well the following spring, I'm reminded that gardening doesn't always need to be complicated.
Don't Bury Those Rhizomes Too Deeply
One of the biggest differences between planting bearded irises and many other perennials is planting depth. I position the rhizome horizontally, spread the roots into the soil and leave the upper portion of the rhizome at the soil surface rather than burying it several inches underground.
This can feel a little strange the first time you plant a bearded iris because every gardening instinct seems to tell you that the poor thing needs to be tucked safely into the ground. Resist the urge to lovingly bury it. Sometimes loving a plant a little too much is exactly how we get ourselves into trouble.
I also give the divisions enough room when I replant. A freshly planted iris bed can look almost ridiculously empty, and it is very tempting to squeeze in another plant or two because surely all that bare soil is being wasted. I've seen what these plants can accomplish in a few years, though, so I'm no longer fooled by all that empty space. The irises will take care of it soon enough.
Replanting My Irises
Once I've decided which divisions I'm keeping, the healthy rhizomes go back into prepared soil with enough space around them to grow. I water them after planting to help settle the soil around the roots, then pay attention to the weather and soil rather than watering automatically on a rigid schedule.
For a brief and glorious period after I've finished dividing, the iris bed looks wonderfully civilized. Every plant has its own space, no rhizomes are climbing over their neighbors and I can actually see soil between them. I usually stand back and admire my beautifully organized iris bed for a moment. Then I remember what it looked like a few years earlier and know better than to become emotionally attached to all that empty space.
What Do You Do With All Those Extra Irises?
Dividing bearded irises creates an interesting problem. You dig up one crowded clump because you have too many plants growing in one place, divide it into healthy sections and suddenly you're standing there with even more irises than you had before you started.
This is where gardeners become very creative about discovering places that could possibly use another iris. That empty corner doesn't look so empty anymore. Maybe the edge of another bed needs one. And of course there is always that dangerous sentence: "I'll just put this one here for now." That's how gardens grow, and it's probably at least part of the explanation for how a person ends up with 500 bearded irises on half an acre.
Bearded irises flowering in my garden.
Why I Keep Growing So Many Bearded Irises
Ask me why I grow more than 500 bearded irises when I'm digging and dividing them in the summer heat, and you may get a very different answer than you would if you asked me in spring. Spring wins every time.
Spring reminds me why I keep growing so many bearded irises.
When the irises are blooming throughout the garden, I forget about the digging, dividing, trimming, inspecting and replanting. I see the colors, the flowers and the way these plants have become part of the landscape over the years.
That's really why I divide them. It isn't simply another job on my garden list. Dividing gives crowded plants room again, allows me to remove unhealthy growth, gives me a chance to reorganize beds that have become a little too enthusiastic and helps keep those established iris plantings going.
By the middle of a big dividing project, I can very reasonably decide that 500 irises are plenty and I am absolutely, positively never adding another one. Then spring arrives, the irises start blooming and somehow all is forgiven.
Happy gardening!
Susan
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