Water: Too much moisture from overwatering or poor-draining soil will cause bulbs or rhizomes to rot and stop blooming. Light: Irises need full sun (6 hours daily) to bloom well. Soil: Irises ...

That said, iris rhizomes are more suitable for spring planting than true bulbs. Spring-planted irises typically grow from rhizomes—thick, fleshy root structures with visible root nodes.

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 ...