Flower Bulbs : How to Thin Iris Bulbs ~ Iris Plant Care Guide
Bearded irises tend to become crowded every two to three years and cease to produce good blooms. Division and transplanting allows the clump to rejuvenate and also provides a way to multiply your iris. It isn’t difficult to do, but it is important to do it at the right time of year to ensure that the iris benefits most from the division.
The best time to plant or transplant iris is after flowering through August. Iris are one of the few perennials to transplant during the hottest part of the year. Established plantings of iris should be divided every 3-4 years or whenever the clump becomes crowded or when flowering decreases.
Bearded irises are relatively easy garden plants to grow and will give good results with a minimum of care, but like all plants, the better the culture the more magnificent the display. The following instructions are easy to implement and should lead to beautiful iris blooms year after year.