never had experience wtih those kinds myself, but you might ask on the Iris Forum.

Best luck!

I'm not sure I correctly understand the situation :-) Did you just plant the bulbs 2 weeks ago? Had they been chilled at all? Are you attempting to force them or is there another reason for growing them inside?

The little bulbous iris are some of the earliest of the spring flowering bulbs to appear. But outdoors, they typically get planted at the same time as any other spring bulb - they need the winter chill period to vernalize and time in the ground to develop a root system. Growing them indoors does not eliminate those same requirements - a chill/vernalization period and sufficient time to develop roots. And that doesn't happen in two weeks.

Can you explain your intentions and processes a bit more and maybe I can give better guidance.

Of course I chilled them. About one month. I brought them to a warmer and lighter place when the stems were about 5 cm tall and I checked that they had a good root system.

Per the link below for weeks of cold period
Iris reticulata
none
Iris danfordiae
14-20

Water the pots thoroughly when bringing them inside. Place pots in a cool area of the home (high light intensity is not important at this point) and leave pots in a cool location until active growth is visible. Take care not to over-water. Once active growth begins, you can move the pots to a warmer location that receives more light. Forcing bulbs slowly is more desirable than placing them directly in a bright, warm location. The quick transition from chilling to warm temperatures can sometimes "blast" the buds, which means everything moves too fast and the bulbs do not bloom.

My guess is that the danfordiae were not chilled long enough. Waiting until they were 5 cm (almost 2") was maybe waiting a bit too long.

Sue

Here is a link that might be useful: Forcing Bulbs-Fact sheet from the University of RI