They produce 6-inch-tall, blue, yellow or purple flowers in early spring in zones 4 to 9. Over the years, these bulbs will naturalize into nice clumps of bloom; just be sure to plant them in a well-drained location.

Will iris bulbs multiply?

Irises multiply fairly quickly and when the plants become overcrowded they produce fewer of their lovely blooms. It is very easy to divide iris plants to rejuvenate them, and for the best display, bearded irises should be divided every three to four years. ... Holes in iris rhizomes could be caused by iris borers.

How do I get my iris to bloom again?

Deadhead the iris frequently to encourage new flowering from buds growing further down on the stem. Let as much of the foliage remain on the plant as possible because it will continue to absorb the sun and feed the stems. Once flowering is over, cut the stalk down to the soil level but not into the rhizome or bulb.