To maintain vigor in iris, they can be divided as much as once a year. Dividing and replanting allows the plant to root in before the ground gets too cold. The process will rejuvenate old plants ...

Because of this, most experts would advise dividing your iris bulbs every couple of years to ensure they don’t get too clumped together. You can then plant these bulbs elsewhere to add more ...

Fortunately it's easy to revive them. Irises spread by underground rhizomes, a storage organ similar to a bulb. Plants can be split apart and replanted in the autumn or spring. It should be done ...