My oldest rugosas are dying. It started 3 years ago with Will Alderman. He was huge, one of the first to bloom, bloomed almost all summer. Then the ends of branches, then whole branches, then whole canes began dying. I'd cut back the dead wood. New growth kept coming up. We made it thru the summer like that. The next year he put out great spring growth, but then the process started up again, and the dying came faster than the new growth. By the 3rd sprig, there wasn't much left and I finally shovel pruned him that June.
Fimbriata, on the other side of the house, whole different environment, went next. Same process. Last year it started on the species, Alba & Rubra, shown in the photo. This spring, I thought I'd beat it, but as you can see, I'm losing.
With Will, I wondered if it could be RRD, tho he showed absolutely no other symptoms, he was on the direct line of he wave that went thru here in 08 and rugosas respond differently to a lot of things. But the others are nowhere near and I havent had any more RRD since that wave. I have several other rugosas planted in the same area as Will was, including a very large Sir Thomas Lipton and so far, they all seem okay.
I also thought it was because I wasn't removing the hips fast enough--rugosas will get some dieback if you don't remove the hips, tho not whole branches and canes--but Fimbriata is pretty hipless and I was very attentive to the species this year.