Out of curiosity and perhaps to a purpose, I wonder which Schreiner black iris is your favorite. I have narrowed to Schreiner because they seem to specialize in blacks.
'Hello Darkness' does well for me and I like the depth of color. So many of the blacks show a lot of purple. It will be opening in a few days and I will try to upload a pic.
Ghost Train Here Comes The Night
I do not know if either are Schreiners irises but I love these two black ones. I won Best of Show with Ghost Train two years ago at our show and have had multiple comments on Here Comes the Night on a better picture of it on FB. Both are a little worse for wear due to late frosts. I love the buttermilk beard on Here Comes the Night. Ghost Train is a great grower.
Grace:
On the left is Don't Stop Believing and to the right is Strawberry Shake. Both are beautiful pinks that bloom late. Don't Stop is really tall. Strawberry kind of leaned sideways due to weird weather but is usually very straight.
I have Dark Passion. It is really very dark purple when compared to Before the Storm, but it looks black in the garden setting. A nice iris that grows well. It occasionally flops under rain, so I am looking for alternatives.