I have cut my roses back beyond the canker, some to the ground. Now how do I keep the canker from coming back? Does the soil around the rose bushes need to be treated? Why is this disease not included with the common listing of black spot and mildew? By the time I found out what was wrong with my dying roses it was CUT THE BUSH TO THE GROUND. Do I need to keep cutting back anything that looks like it might be canker? Or will spraying stop it? Spray with WHAT?
Roses, Disease, Canker
Where I live it is pretty common to prune back my rosebushes to within an inch or two of the ground each year. The rose canker seems to like to attack the rosebushes when they are most vulnerable, such as when going dormant after a hard frost or freeze and then again when they are first trying to break dormancy and come on in the early spring. When they are stressed in some way it will flare up as well. Using a good fungicide spraying program will usually keep it in check, along with some careful pruner cleaning between each pruning cut especially when the disease is very present. Here is an article about canker and ways to prevent its spread: https://www.gardeningknowhow.com/ornamental/flowers/roses/rose-canker-fungus.htm
For good fungicidal sprays to help guard against canker I use Banner Maxx, Honor Guard, Immunox or Green Cure. Usually you will want to start with something like Honor Guard or Banner Maxx, then follow up with Green Cure applied at the Cure Rate about 12 days after the Honor Guard or Banner Maxx application. Banner Maxx and Honor Guard are really the same thing, Honor Guard is the generic and also less costly. They may be found on-line at http://www.rosemania.com .