why didn't my siberian iris bloom this year?

Question

I have maybe a 100 square ft area with siberian Irises, this year none of them bloomed. the are gets 6plus hours of sun, lightly shaded in the late afternoon. There is also a crape myrtle, redbud, fig and leyland cypresses in the same bed, they are fine, the iris leaves, are growing beautiful, just no blooms. I divided them 2falls ago, but they bloomed great last year. they only thing I did different was i used preen early in the spring. Any one have any answers?

Thanks

Answer 1

every spring we use a little dried composted horsemanure and a little lime...............they are not listed with that name for PH  for them is 5.0-6.5..........I would test the ph for them.........................I think the Preen had something to do with them not blooming........it is a weed killer...................