I bought 5 Knockout roses last year; they are all dead.

I have 3 Knockouts and they are all doing great! And I planted 6 Knockouts at my parents' house in north Central Indiana last summer and all of them survived their cold winter and have been blooming non stop this summer!

And yes, I would contact your County Extension Office for more information.

I have 50 of the sunny knock outs and one blush that are all on an automatic drip for 2 hours every other day (which equates to about 3 gallons of water each) they aren't real happy and the flowers are pitiful but so far no deaths (knock on wood). I have two more blush ones that are not on the drip and they are alive but have very few leaves and may not make it.

I hadn't heard about a disease, I assumed our trouble was drought related. Please let us know what your County agent says...

I'm in Dallas, and have lost one of my three Knockouts so far this summer, as well. One other one is looking pretty good, and the last one isn't looking very happy at all.

Knock out are fairly disease resistant but they are plagued by mildew and fungus. A few problems I have caused in the past with my roses are fertilizing at the wrong time. I hit my rose during the hot summer with a small amount of color star fertilizer and about killed them. I also made the mistake a year later with neem oil in the hot summer sun.. big mistake. This year I am just leaving them alone. I do have some yellowing leave and I need to find a fungicide I can spay during the hot summer day but I might just wait and let it work it self out.