2016-08-10 / Columns

Garden Scene with Peggy Bolton


Some tall bearded iris were beautiful this season. If you have lots of leaves and no blooms, then it may be time to lift and split them. Over the years, iris tend to clump so tightly when they are happy that they give up flowers for green. Many varieties will need to be separated, cleaned and replanted every two or three years. If a clump has never bloomed, it is probably planted too deep. Make sure to replant close to the top of the soil so you are able to feel the top of the rhizome with your finger.

It is best to divide iris after they have bloomed and the foliage starts to yellow. In most cases early August is a great time to do it. Working after a rain may make them easier to dig. Make sure plants are back in the ground right away, so they have time to root in before winter.

After blooming, cut the old bloom stalk back to the rhizome. Cut the leaf tops to about six inches tall before digging. Rhizomes will be close to the surface and growing away from the plant so be careful not to stab one when digging. Lift the entire clump from the soil with a spade or garden fork. Once the clump is raised, hose off all the soil, making the crown easier to work with. It will not hurt the washed roots to dry in the sun before working with them.

Use a sharp knife to remove and discard all diseased and damaged rhizomes. Any that are shriveled or soft should be cut out. There may be signs of rot, promoted by all the excess moisture last fall and again after some of our torrential rains: this must be removed. Look for iris borer damage and cut out any infested plant parts. Borers will leave indents and partial holes and tunnels in the rhizome which can lead to rot.

Try to leave a ‘Y’ shape for each division. Soak cleaned roots in a water/bleach solution of 10/1. This will help prevent future disease problems. Dry rhizomes in a sunny location. Do not replant until they have totally dried.

When replanting the iris, keep the rhizome close to the surface to promote blooming. Remember, they grow an entirely new root system. In most cases iris will start to bloom next season.

Send questions to: Country Grown Perennials LLC, Peggy Bolton, 4801 Pines Brook Road, Walton, NY 13856. Enclose a stamped, self-addressed envelope if you wish to receive a personal reply. Visit us on the web at

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