It's not uncommon for Blyth iris in my garden to exhibit "tight" branching. Not all, or even most, of his varieties do it, but enough of them do that it is a noticeable trend. It doesn't seem like he considers tight branching to be a serious flaw. Or maybe the plants don't exhibit that trait in the ideal conditions of his own beds? Who knows.
As far as bloom season goes, some of his varieties have long bloom times, some don't. I don't really notice any pattern there compared to other hybridizers. Enjoy The Party, for example, has branching that I consider to be a bit too close, but it's one of the first to bloom in my garden every year and will still be blooming late into the season.
