I planted six irises last year, two each of three different varieties. On the Sea of Love, some of the blooms came up partially or totally wilted (rotted?). You can see in this picture that the upper bloom is mostly yellow, and yucky looking. The other blooms and the leaves look ok - perhaps a slight bit of leaf spot on some of the edges.

None of the web sites that I've looked at for Iris problems talk about problems affecting just the blooms like this. I've already cut and disposed of the stalk on the other plant, which was shorter and only put up three blooms. These two happen to get the least sun of the six I planted, but I don't think there's a huge moisture problem.

Any ideas what the cause and cure might be?