Posted: 22/04/2015 at 18:33
Black spot travels in the air. My roses got it and nobody else is growing roses in any of the surrounding houses. Its just one of those things unfortunately. You could try growing resistant varieties. Make sure you clear all the dead leaves in winter as the spores can overwinter in the dead leaves.
I spray my roses with a mix of sodium bicarb and washing up liquid. This will stop uninfected parts of the rose for catching it but will not cure diseased branches. You can also use rose clear. Climbing roses tend not to be as susceptible as the braches tend to have good airflow around them stopping any damp conditions the fungus loves. Pruning bush roses to have an open centre improves airflow. You could also prune out infected foliage
I have found as my roses have established more it hasn’t been such a problem. Digging them up has probably weakened them making them more susceptible.
What type of clematis did you try as clematis montanna are much easier to grow than other species and may grow well if watered well in the first year.