To commemorate Labor Day, we often take on a project that is, well, laborious.  It is not always planned in advance—we do most of our intensive outdoor work on weekends anyway—although we rarely celebrate Labor Day in the traditional way by relaxing and doing nothing.  This year’s back-breaking task:  dividing the Siberian irises.

Why would we want to do this?  Good question.  The irises were a gift from a local stonemason, Mario, who did a lot of work for us about seven years ago.  Part of his work included the formation of our ornamental gardens and when he was done, we had a lot of space to fill.  In addition to being a talented stone worker, Mario has a dark green thumb.  To help get our new gardens started, he brought us many cuttings from his own garden (which is like what you would see at an Italian villa), including the irises, a Japanese maple and sedum (to plant in the crevices of the stone walls he built).

It took a few years for the irises to establish themselves but for the last three years, they have been producing a dense display of purple and white flowers each spring.  The irises are very effective at naturalizing themselves and after seven years have densely filled the areas where we planted them.  However, as their root systems become more and more compacted, they will flower less abundantly.  Typically, Siberian irises form rings of active plants with dead roots at the centers.  Ours were beginning to display this characteristic.

But digging them up, dividing their rhizomes and replanting them ensures that the irises continue to flower profusely.Separating the plants also means that we can spread them out over a larger area (expanding the border that follows the south edge of our main garden, for instance) and transplant them to new locations (along the road, perhaps).  Further, we’ll have enough split rhizomes to share them with our friends in town to whom we promised the plants last year.  We let that season pass before we could get to them so we are overdue.

The task is decidedly labor-intensive and required several steps.  First, we dug up the irises.  Their rhizomes and roots are densely intertwined and form clumps about two feet in diameter.  Removing them is almost as difficult as removing sod but their stems and leaves allowed Rachel to pull up on the irises while I broke the roots free with a shovel.  It took about half an hour of picking and tugging to break each mass free and lug it out of the garden bed.

Next, I broke up the root masses using a small gardening fork and my bare hands.  (Actually, I wore work gloves.)  If we had not let the irises go so long—two to three years is the recommended interval—this part might have required less effort.  But after seven years, the root masses were practically solid.  I used the fork to knock out the trapped soil and rocks and create handholds.  Then, I just grabbed on and pulled.

Slowly and with not a little frustration, I broke small groups of rhizomes free and passed them over to Rachel.  Using shears, she cut off the excess roots and dead portions of the rhizomes, clipped the leaves to a length of about six inches, and stacked the now divided plants neatly on a tarp.  We filled two shopping bags full of irises and delivered them to our friends in the village.

The final step was replanting.  We returned about half of the irises to their starting place and reburying them in the loosened soil was the easiest task of the day.  We spaced them six to eight inches apart and consequently, the area is much less densely-planted than it was when we started.  Given past experience, though, it should fill back in over the next few years.

The remaining half—and the two clumps of irises that we have not yet divided—will have to go somewhere else.  But that is for another labor day (one with a lower case L).

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