After moving house a year ago I inherited about 40 rose bushes in beds from the previous owner. Been a gardener for years but knew nothing about roses and since last year have learned a fair amount.
In one bed there are about ten bushes which look particularly weak but the rest are fine. Judging from the stumps I reckon all the bushes are a good 15 years old and probably pushing 20.
A lot of effort has gone into these bushes since last year and up until two weeks ago everything was great (post first flush) and then the dreaded black spot kicked in.
Even the new growth has it. Trust me I have done everything I know (feed, mulch, good pruning plus black spot duty all last year too). I resisted chemicals until the first signs kicked in and then sprayed. Even that hasn't halted the dreaded BS.
After hours and hours of BS removal and something now looking like the Somme. I am thinking about giving up and starting again with new bushes.
So the question is, start all over given the age of the bushes or persevere with it for another year. I do like a challenge but given the effort so far it has not really been rewarded.
Finally - random point - rose clear ultra states every three to four weeks (April through to September) and also every 14 days if disease/pests evident. Then it says in big black writing - maximum number of treatments: 4 per year Confused. In theory by the time of first buds and spraying, it will still be the first flush and then that's it treatment over for the season.