Stem Canker
This is seldom seen on younger well-tended roses, occurring most frequently on mature plants with a high percentage of old wood.
It manifests itself in the form of gnarled, swollen lesions, often with surrounding dead and furling bark. Canker will usually appear where there has been exposed tissue at sites of previous damage, such as at the union where the plant was originally budded. If the stem on which it appears is expendable simply remove it, but frequently the canker will appear in awkward places that are impossible to prune away. If the plant is important to the garden the only solution is to carefully cut away the damaged tissue. Use a sharp knife for this and keep on removing layers until only clean pith is left. Cover the scar with grafting wax to prevent other infection entering. If the rose is not important the easiest solution is to dig it up and burn it.
