Not in your zone but I recommend planting immediately. Even if you only get foliage this season it will ensure the bubs' vitality. If they don't overwinter in your zone be sure to let the foliage yellow before digging and storing.

Definitely plant them now. I planted some last year in February (but I'm in a warmer zone than you, so my February is like your March :) and got blooms the same year. Not sure if yours are blooming size or not, but perhaps. Either way, they probably won't survive to the fall out of the ground. They need to "eat."

However, mine this year they've put out some pathetic looking foliage so far and I don't know that they will bloom again. I've heard someone else mention the same problem - they only get one year of blooms from theirs, and they just buy new each year because they liked them so much. Perhaps it is too warm here through the summer for them to come back like and bloom again.

Oh, but they are hands - down gorgeous! ! Good luck to you with yours.

I don't know if I will be helpful here or not. But, here goes. I planted Dutch Iris Bulbs for years, as annuals, never realizing they will not only overwinter here, but will multiply. Back then, they were in perennial beds that I was constantly stirring with dividing, planting, exerimenting, and such. I guess I destroyed the bulbs with all the tinkering.
I put some new ones in the ground about five years ago and they did not bloom the first year. Or the second. But on the third year, they were glorious and I now have really big clumps that I will likely divide and spread around this year. I live in east Central Mississippi, Zone 8a. I assume that the bulbs may have been too small to bloom the first couple years.
They come up every fall, the foliage stands all winter, and they bloom in late spring, which is about mid April here.

Hope this helps someone. I am guessing that they really are not winter hardy in Indiana.