Yellow Flag

Continuing the yellow theme, this is yellow flag, or sometimes just flag, which appeared in the garden uninvited but not unwelcome.
Iris pseudacorus looks best in large groupings, as it is usually found along the edges of watercourses or damp ditches.
In our garden it looks as though it was badly planted, about two metres from the pond. Perhaps I should reunite it with its cousins in the autumn...