Yeah , sometimes, when something gets crossed a bit too much, they may eventually just become sterile, or nearly so. I've come across it before & encountered that, with other plants. After I posted, I read an interesting couple of article, in Mariposa, Iris gardens, up by Yosemite...May want to give it a quick "read", including about "lines" ( I say "veining") & how to work with that, if interested..
