Thanks for the replies. I bought these roses about 15yrs. ago, Alex Mackenzies. They are hardy roses. We do get winter kill as the temp will drop to -35 celsius a couple times over the winter, so I have always had to prune them in the spring and up until a few years ago they would always come back. Forming a hedge about 6ft high with lots of blooms. They just seem to be slowly petering out. I keep a eye on them for pests and diseases. I thought I would give them one last year to bounce back.
If I apply rotted sheep manure should I not apply epsom salts?