Have some pictures from last week when the th flowers were still very new - now there is much more but I'm at home nursing a cold.
In German
Iris pseudacorus is called Sumpf-Schwertlilie or Gelbe Schwertlilie or Wasser-Schwertlilie (swamp, yellow or water sword lily). For some reason even though they are not closely related to lilies, the whole genus of
Iris (a word which is in use in German, too) = Schwertlilie. I can see where the sword comes from - the leaves.
Well, the yellow iris or yellow flag is quite common around here - and it is an invasive species in other parts of the world.
( Pictures )