The time to work with various Iris is upon us and there is no better time. Bearded Iris require division every 4 to 5 years and are greatly enhanced once split into healthy roots or fans. Both Siberian and Japanese Iris seem to prefer spring division but can also be dealt with now.

Siberian Iris form dense colonies of rhizomes which are very woody, requiring a lot more tugging and cutting as well as sharper tools. For this reason experienced gardeners have chosen spring to conquer and divide Siberian Iris. Winters freeze and thaw cycles usually soften the roots. When working with iris early in the year, do so before the foliage reaches 6 inches in height.

The Japanese Iris or Iris ensata are very obliging and easily divided, their roots are softer, more fleshy. They can be divided spring or fall just remember to follow the same rules with foliage height.

As for bearded Iris, now is the time. If your clumps have produced fewer flowers and have been left undivided for 5 years or more, there is no reason to wait. Tools for the job include: a shovel, good clippers and a large bucket filled with 90% water to a 10% Clorox solution.

I prefer to lift the clumps in large pieces and inspect the roots for soft rot and Iris borer. I pry and prod the rhizomes, sometimes using a small twig to open up soft spots and allow the cavities to dry out. Borers are common in bearded Iris and are remarkably large. Many of you have devised methods of dealing with slugs, I say proceed there with your borers, no need to share the gory details.

The best sections of the Iris are the newer roots, after digging a few clumps you will notice that many have a network of very woody, older rhizomes. The task at hand is to separate the young, more pliable rhizomes from the derelict older roots and replant just those.

The top of the rhizome prefers to rest at or just below the soils surface and you do not want to mulch over the top of the rhizome. Bearded Iris prefer to grow south (as do others) and it helps to face the fan towards the south with the rhizome behind.

Every piece must have an active growing tip with some foliage at the end of the rhizome. Before you reset your new roots, break up the soil in the bed, add amendments (like compost) and soak your fresh divisions in your water/Clorox solution. This will clear up any remaining soft rot.

Tamp your soil down around your newly placed roots which can be placed 1 to 2 feet apart. The foliage can be cut back at this point, new leaves will arrive on new growth tips shortly.

To avoid borers in the future, always cut back the foliage of bearded iris in fall and compost them or put them in your trash. The moths than grow into the larvae lay their eggs on the leaves in fall.

Gardeners are frequently left with far too many roots to put back in the same spot. For a brief (or not so brief) moment you may consider getting into the Iris business. Go for it, I say!