Backyardmomma,

I am still here. : )

I am not a rose expert like Sammy, and I hope she and others who grow lots of roses see your thread and respond.

I have had the fungal infection that causes black spot on the foliage of rose leaves but haven't personally seen it on canes, although I suppose since it can attack the foliage, and we all know that it does, then it likely could attack the canes too.

However, there are some rose cankers that attack the stems and they can vary in color from shades of brown to purplish to black.

I'm not sure which of the two you have, or if it is something else entirely. With last year being so extraordinarily wet, humid and cloudy, I am not surprised the roses have issues.

I have linked the OSU Fact Sheet on roses for you and it describes the various diseases, including canker, and what to do for them. Fungicides are already on the store shelves and I'd buy one that lists roses as one of the plants it is approved to treat, and I'd follow the directions on the label. If the fungicides are not effective at cooler temperatures, they'll so state that on the label and tell you to wait until the temperatures reach a specific level.

Because diseases like black spot and canker linger on plant litter, be sure to rake up and dispose of all of last year's leaves and this year's prunings. I wouldn't compost them because I'm not sure if the compost pile will heat up enough to kill them. I'd bag them and get rid of them. When you prune, be sure to disinfect the pruners in a water/bleach solution after each plant so you don't spread the disease from plant to plant.
It probably would be a good idea to be very pro-active and try to get ahead of the diseases this year by treating all your roses regularly with a fungicide as the product label advises. With a very wet year in 2009, and with 2010 starting out with above-average precipitation, it is likely that there will continue to be lots of fungal issues on all sorts of plants this spring and not just on your roses.

Good luck and I hope the roses make a nice recovery.

Dawn

Here is a link that might be useful: OSU Factsheet on Growing Roses

I'm with Dawn. Sounds like cane canker. The canes will need to be cut back to below the canker, because any growth above the canker will die anyway. After cutting back the canes to healthy cane, just give your rose an extra bit of loving care with bonemeal, cottonseed meal, alfalfa meal or the like to give them a boost for the growing season. And do everything else Dawn said, a good dose of fungicide. I like the systemic kind.

Marcy

Knock Out roses are not supposed to get blackspot. People say that they are very hardy, but in Tulsa, I often have to cut mine back almost to the ground. Sometimes I put a little fence around the base of the rose so it won't be stepped on by animals until it begins to grow. They grow back fast, and are very hardy.

I absolutely refuse to spray. I have probably discarded over 200 roses in the past few years, and will not spray. My 10 Knock Outs do fine with no spray, and the three Blushing ones were fine until they were replaced by tomatoes. I bought mine in one of the first years they were sold.

For what it's worth, when you prune roses that are together in a bed, you need to be aware of where the sun is. You may need to prune those around the one rose so that they can all get the sun. I pruned way back a rose that was between some roses, and it died because it did not ever get the sun. The larger roses around it completely shaded it.

SAmmy

Sammy and I both have been growing roses for some time. Awhile back she went no spray in her garden while I've tried to go low spray in order to have more varieties in my garden. When Sammy and I speak of spraying we almost always are talking about spraying with fungicides. I seldom if ever use an indiscriminate insecticide on my roses. So with that explained I just thought I'd speak a little about fungicide options for those who do want to use it on their roses. I don't know if what you have is B.S. or canker, but B.S. has been shown to overwinter on canes and when conditions are right, germinate and infect the new leaves. If you need to spray a fungicide you might want to try Ortho's Rose Pride (formerly called Fungunex). It is a preventative not a curative so you will need to have it in place on the roses before BS season heats up. It also is one of the best for powdery mildew (on Crape Myrtles too), but you do not want to start spraying it until temperatures are 65-70 degrees. As with all fungicides repeated spraying at the manufacturers recommended intervals during prime diease time is required for adequate protection. Another product I've heard miraculous things about is Bayer Disease Control for Roses,Fower,& Srubs with Tebuconazole. Do not get the product that also has the insecticide in it. The claim is that Tebuconazole actually cures an existing blackspot infection. I've had only limited experience with it myself, but if BS has gotten away from you, you might want to give it a shot. As with all spray materials that I can think of at this time, the temperature plays a key part on when you can spray, so make sure you ask if you are uncertain if it's warm (or cool) enough to spray.