It is a simple yet effective way to separate those Iris you missed last Summer and Fall. You find a clump that is overcrowded and struggling and you want to divide it. You don’t divide Iris in Spring!Click to see full answer. In respect to this, can you transplant irises in the spring? Don’t Transplant in Spring Because you need to cut away the foliage when transplanting rhizomes, the spring is a bad time to transplant iris. Irises flower in spring, sometime between April and June depending on the cultivar, and their foliage does not begin to die back until July.Similarly, what is the best time to divide irises? Mid- to late-summer is a good time to divide bearded irises. You want to make sure that the roots have ample time to grow before winter. You can usually tell that your irises are ready to be divided when a clump looks overgrown, with rhizomes starting to grow into each other and popping up from the soil. In this manner, how do you divide and replant irises? To divide your iris, start by lifting the clump of iris plants out of the ground with a spade or fork. If possible, lift the whole mass out whole, but if you are unable to do this, carefully break the clump into smaller parts and lift these out. Next, brush of as much dirt as possible from the iris rhizomes.How do you propagate irises? Use a fork to dig up a congested clump of irises. Pull the congested rhizomes apart by hand, or cut them with a knife. Newly-planted rhizomes are vulnerable to wind rock, so it’s a good idea to reduce the leaves by half. Replant healthy rhizomes about 12cm apart with the leaves facing towards the sun.