You have a mix like I have - the blue irises bloom first, then the
yellow. When I thin a bed, it takes longer for the blue irises to
bloom again by a couple of years. So when I last thinned the be, I
had yellow irises the next year and blue irises two years later.

On Mon, 27 Apr 2009 19:31:38 -0400, Phisherman
wrote:

My iris bed is in full bloom. Blossoms were yellow last year now they
are blue. What causes this and will they be blue again next year?