Posted: 01/08/2014 at 12:03
It seems a particularly bad year for blackspot, I've got a mixture of about 15 roses, many of them DA's and most have been affected. This year for the first time I started spraying with Roseclear early in the season every 2 weeks, but it's not always possible to keep strictly to this routine due to rain, being away etc. and I don't like using too much spray anyway. I do try picking up the dead leaves underneath - not always easy in the middle of a mixed border! and I mulched every rose this year with a thick layer of manure/compost thinking that would do the trick, but not, it seems. I have quite a windy garden in the south west here which you'd think would help.
I've decided just to live with it, although I might try David's suggestions, the roses have been in for 7 years and none have died of it yet, they all flower very well - apart from my Margaret Merrill- which is supposed to be just 3ft tall, mine is reaching 6 ft, lanky with no flowers - don't know why.