Now Is the Time to Dig & Divide Iris

Iris need to be divided before they become overcrowded and bloom starts declining. Some varieties may crowd out others and disease problems will be aggravated.  In the Midwest the best time to divide the clumps is 6 weeks after spring bloom or generally in July and August.  The iris have now set the bloom for next spring and have reached a dormant stage. The new roots must also have time to get established before the ground freezes.  If the weather is very hot and dry, you might want to wait until Sept. when the temperatures are cooler.  If ordering new iris and they arrive on a hot day in July, just plant them in a pot with garden soil and replant in the garden after the weather cools.Clumps may be divided by removing older rhizomes from the center and leaving new growth or by digging the whole clump and replanting the largest and healthiest rhizomes. It’s nice to have 3 new divisions to start again by planting them in a triangle with the narrow ends toward the center. New growth will complete the clump in a year or two.  Just toss the older-dried up sections and if you have extras, share with a friend. Be sure to write on the leaves the name and what color they are as they all look the same after bloom is over. The best way to grow iris is in a sunny (4-6 hrs. of direct sun), well drained location. They will tolerate some shade but bloom will suffer.  If shade is a problem look for varieties that will grow in the shade.  Iris should be planted so that the tops of the rhizomes are at soil level and the roots fanned out under them to help hold the new plant in place.  In hot climates or sandy soils up to an inch of soil may be helpful. A very common mistake is to plant them to deep.

The rhizomes should be planted at least 12” apart to allow room for growth without crowding each other.  Water the new plants thoroughly and often until the roots have been established and new growth has started. Once established iris don’t normally need a lot of water. Overwatering can cause rot and several other problems.The American Iris Society’s web site www.irises.org is an excellent source of information. The Hutchinson Iris Club members will also be happy to help. Check out their rhizome sale Sept 20^th at the Farmer’s Market. Be sure to stop by !!! Submitted by irislady.