[header] How to get irises to bloom [title] Be aware that irises need to be divided. [step] The first and most likely cause for irises failing to bloom is overcrowding. Irises must be dug up, divided and replanted every three to four years. 
[substeps] If this does not happen, it becomes less likely that your irises will bloom. [title] Cut the leaves down to a height of six inches.