I am a casual gardener and live in Mission BC. I have miniature roses in a pot on the sundeck which has southern exposure and receives lots of sunlight. About 6 weeks ago, one of the roses developed Black Spot. I treated it with a Fungicide which seemed to help. I repeated as directed and the plant seems to have recovered from that. The problem I'm noticing now is that the petals on the roses are curled and the leaves are turning yellow and falling off. Any ideas??