Iris Katherin Hodgkin fail

[Marb67]

I bought this iris last year which had a lovely yellow blue flower. It failed to come up with a flower head this year so I pulled up the bulb with no signs of anything wrong. Why didn't it flower, or even get any larger?

[mothhawk]

I've tried to grow packets of Dutch iris three times and failed to get a single flower every time. I searched the web and came to the conclusion that right from planting, whether in a pot or the ground, they must be in full sun the whole time. The description will say they tolerate dappled shade; well yes they grow, but do they flower? I don't believe so.