It's a beautiful blue ...

Iris histrioides, very closely related to yesterdays backblip Iris histrio which has very long leaves at flowering time while this one has very short leaves at flowering. Both are a beautiful blue.

Iris histrioides is grown more widely in gardens but is not anything like as common as Iris reticulata of which there are a good number of named clones on sale cheaply in the autumn. Iris histrioides usually has bigger flowers most often in this rich, royal blue.