Answer: When iris become overcrowded, they can stop blooming. Dig and divide your iris as early as possible this spring. Then, every 3-4 years, divide them in late summer (usually August) and replant. Iris grow from fleshy rhizomes and continue to put out new growth from both ends of the rhizome. The new growth is what develops flowers. If the rhizomes have no room to develop new growth, they won't produce flowers, either. Carefully dig the rhizomes and divide by cutting off both ends and discarding the old center portion. Trim the roots to about 6 inches and replant in a freshly amended garden bed. (Amend the soil by digging in plenty of organic matter.) Plant each piece just below the soil level, spreading the roots out naturally. Just barely cover with soil and top the bed with several inches of mulch material to help retain moisture and suppress weeds. Once the plants become established they will develop flower stalks. When the flowers shrivel, cut the flowering stalk down to foliage level. Be sure to supply adequate moisture during the growing season by applying one inch of water per week to the iris bed. Following the above guidelines should restore the glory of your iris garden.
Q&A Library Searching Tips