I dug up some ordinary blue bearded irises from my garden and replanted them else where. For about 3 yeras they were fine, then last year some came up white. This year nearly all of them are flowering white. Any ideas as to why? Anything I cn do to make them revert to blue?
Are you sure they are the same plants? Have you checked the rhizomes. They could be seedlings, mixed in with the originals. Just a thought.
I've heard of this happening before, but have never found out why, so I decided to do some googling which produced this link http://pennhort.libanswers.com/a.php?qid=186466
I have no idea of the horticultural/scientific background of the posters but the answer is interesting ............