Advice for stem canker
A friend of a friend came to me with this dilemma. She was pruning her roses in advance of the Santa Ana winds. When she got done she noticed some canes had funny areas and so she looked it up and it was stem canker. This was on 3 roses she thinks. She did not disinfect the pruners but used them on all the plants. She was wondering if she should spray the whole garden down with fungicide.
Did she spread the canker with the pruners to all her roses? Should she go back and recut the canes with clean pruners. It would take time but probably not generate a big volume of trimmings if she cut just a little more from each cane. Is it too late anyway and the canker is working it's way down every cut?
I never had stem canker and so I didn't know what to say except to remove old mulch and spray and then feed the plants to get them actively growing.