Last year I almost killed a ton of bushes with too much fertilizer. I checked the soil and the salt content was sky high and the ph had dramatically dropped. I spent the rest of the summer dealing with my toxic soil. I am not saying that is your problem but I was surprised to find I had this problem and it can kill plants quickly.

I lost one (Josephs Coat)to fire ant powder earlier in the season. :-(

alotofplants ---- You should try organic fertalizers! They work better with the soil enriching it instead of making it toxic!

I had the same thing happen to me. In my case, my roses were climbing over and through a fence. The "person" on the other side sprayed it with RoundUp as they though it was a "vine". The entire bushes died just as you describe. Is this possible in your case?

Here is a link that might be useful: Perennial And Rose Gardening

Bob, did you check the root systems? Voles will eat rose roots down to nothing and what you describe sounds like vole damage. Or, there are tunnels and they took enough soil away from the roots that they couldn't get enough water.

Thanks for the suggestions and observations, folks. Unfortunately, nothing that was mentioned sounds like the likely murder weapon. As I mentioned, the root system didn't display any damage. Moisture was fine. Fertilizer schedule was precisely the same as in previous years and the plants have thrived (notwithstanding ocdgardener's apparent disdain for inorganics). No Round-Up nearby. Don't have fire ants in our area.

It's a mystery!

Bob

Because of your part of the country, consider the possibility of the "sudden oak death" pathogen that has been proven to affect roses among the many plants it harms.

Yes, call county ag extension and ask the Master Gardener if the oak disease is likely in your neighborhood. It can be in the soil even though the trees were cleared long ago. Roses can be grown in large bottomless pots sunk in the ground.

Two good suggestions...thanks! I hadn't thought about armillaria (oak root fungus) but that should have been my first suspect. One of the rose bushes was planted within three feet of the rotting stump of a century oak that was cut down two years ago. And I know we have this fungus in my neighborhood; it's an oak forest.

As for the county ag department, I never seem to think of them, relying instead on my garden books and the web. But they're an obvious choice for getting an answer to a specific question from someone who's knowledgeable in local growing conditions.

Thanks to all who took the time to respond. The internet community is so generous with their assistance; I'll try to repay by offering whatever help I can in the future.

Bob

"Sudden Oak Death" is actually a different fungus (phytophthera) from Oak Root Rot Fungus (armillaria). I am afflicted with armillaria in my front garden. In 1998 I planted 70 roses in that 25' x 60' area, and in 2002, the first one inexplicably died. After a few nearby roses died shortly thereafter, I had my county extension agent come out for a diagnosis, and he confirmed armillaria. Ground zero for the dying roses was the spot where we had an 80' pine removed and ground out the previous year. The roses continued to die in an outward pattern from this spot over the next few years. We have multiple theories about why this fungus is so active in this area, which I won't go into here. Anyway, armillaria fungus is endemic in many areas of Calif. I have since replaced all of the in-ground roses in that area with 15 gallon potted ones sitting on stepping stones. I was sad to lose my in-ground roses in that particular garden, but as a trade-off, I now have 180 roses in an area that I used to have 70. Gotta love that smaller footprint in some ways. It's pretty spectacular. The ancillary in-ground plantings are variable in their susceptibility to the fungus. Many things resist it quite well, although I lost some of my hydrangeas to it. It's been a very long 5 year journey of research and dealing with it. I could write much more on my experience with it. Hope this helps.

I'll vote for armillaria in this case, but on the subject of sudden death generally, here is another cause. I've found that roses bought at [local] nurseries that do their own bareroot potting often suffer from air pockets 6 months to a few years later. The nurseries often use a light soil and don't compact sufficiently around the roots. After a while, this soil compacts downward on its own, leaving airpockets around the roots. You start getting unexplained dieback, often rather quickly. The larger the container, the worse/faster it can be. So now I check every three months. If you can stick two or more fingers into the ground and meet little or no resistance, pack soil into " fingers holes."

Well, short of replanting following Susan's potted plant solution, it looks like my only alternative is to consider some armillaria-resistant shrubs. Can anyone offer some suggestions for plants that would provide long-season color, a similar size and armillaria resistance? (I don't ask for much, do I?!)

Bob

P.S. Thanks for the warning about air holes, catsrose. I'm not sure I've ever experienced that but it's good to be forewarned.

Before you assume that you have armillaria, do be sure to get an actual diagnosis from your county extention agent or other qualified person.