Are these own root roses? Where they planted at about the same time? How old are they? Do you feed them or the lawn near them?
Nik

Cats,
I've read several threads - I'm linking one - on rose stem girdler which is a problem esp of hybrid rugosas. I've never seen it myself, but I watch for it on the rugosas I have.

Here is a link that might be useful: old thread on rose stem girdler and rugosas

Many years ago a rose friend was looking at my Dainty Bess, and I remember telling her that it was declining. Nothing that I tried seemed to be working.

She told me that Dainty Bess did not live for that long. She indicated that some roses just simply have a number of years to live, then they die.

After that I began hearing on this site about the importance of making major cuts in the base of a rose to encourage new growth.

I feel certain that you would be aware if your roses would only live a certain amount of years, and also that you would be aware to make those major cuts.

I just thought I would throw out those two ideas to you.

Good luck in finding an answer.

Sammy

My roses are all own root. The rugosas hit so far are 7-9 yrs old. I rarely feed the grass and neither Fimbriata nor Will Alderman were near grass. I am no-spray. All the dying canes you see in the picture were a healthy green and in full bloom a month ago. I haven't found any sign of borers and the pith is clean--just drying up. The roots are firm, so much so that digging the stumps out on Will & Fimbriata was a real chore! I am in clay, so root rot was a possibility but no sign of it.

Have Chilli Thrips made it up there? They will kill a rose, and the canes die from the tip down. I think they are only active in hot weather.

this may sound wild, Catsrose, but I noticed that it looks like you have an asphalt road next to the rose - is there a chance when they put in the asphalt they shoveled a lot of asphalt chunks into the ground and then covered over the ground with dirt? If the chunks are pretty far down maybe the rugosa roots just hit them and the plant is being poisoned from the petroleum in the asphalt chunks.

I have some areas in my yard where asphalt chunks were used to stabilize an edge of the yard. When grass wouldn't grow there I dug down and found huge asphalt chunks six inches below grade. Anyway, just a thought.

I had that happen to a Jen's Monk a few years back...never did find an explanation. Same deal...sudden cane death in a well established Rugosa.