Posted: 18/07/2014 at 17:11
Sizey, many of my customers have had problems with black spot this year, I do the following and it works, remove and burn all affected foliage and any leaves on the ground, spray with fungicide, and include the ground around the plant, mulch heavily and feed with a rose food, water well and although it will look sparse and poorly for a while it will recover. If infection comes back, again remove the affected leaves and blooms if necessary, and respray. If you keep on top of it you'll get results. The lack of frost last winter is to blame as the spores which are usually killed by frost stayed alive. Also make sure there is good air circulation around the rose.