I'm having better luck cross pollinating these Bearded Irises this year.
Usually the purple ones are wilting just as the yellow ones are opening. So I'm lucky to have 1 or 2 flowers to work with - and i'm not even sure if they'll give any pollen. This year I'm certain I got some pollen from Yellow to Purple. But I've heard it's something like a 30% success rate.
It occurred to me that they might be sterile. Because in all the years we've had them, I don't recall seeing a seed pod from self-pollination. They're just spreading out through rhizomes - the roots.