Back in well-deserved favour, the bearded irises are an important part of our planting schemes, particularly in hot, dry gardens. Left to their own devices, however, they become congested, woody and old, flowering poorly.
Although not a clump forming perennial, they are one plant that responds brilliantly to regular division every two to three years.
For the best results bearded iris should be divided after flowering in late January /early February in most areas. Division can be undertaken at almost any time but to allow the plant to develop a good root system and to store sufficient energy to flower, divide in summer after flowering has finished.
Lift the rhizomes lift with a fork and shake free of soil, then tease apart. Taking a clean sharp knife, cut away sections at least 10-12cm (4-5in) long with a good root system attached. Discard old and any diseased sections of root.
Select strong, healthy rhizomes with a good root system attached and reduce the leaves to a fan about 15cm high. Replant in fresh soil; make a shallow planting hole, making a small ‘bump’ for the rhizome to rest on. Spreading out the roots to each side. Cover the roots with soil and bury the rhizome only to the original soil depth. Water in well.
If you are not sure of their eventual home, bearded iris will wait for a new home in cool, airy place. Avoid leaving rhizomes in bright, hot sun and never wrap in wet papers or they will rot. You can pot them up and then the next move is easier on everyone.
Aftercare As with anything newly planted, new divisions require a little more TLC than usual. To help them recover from the trauma of being ripped apart make sure that you mulch well, but do not cover the rhizome. Don’t let them become too dry, or waterlogged for that matter, until well established and making strong growth.
Enjoy Healthy divisions of bearded iris should flower the following season, so enjoy!
Iris are invaluable in hot, dry gardens
Bearded Irises repay regular division
Crowded irises flower poorly; divide and give space to young rhizomes
