Hi this is my first year growing roses and I have 2. One is a knockout yellow rose bush and it is doing great and is absolutely beautiful. My other rose bush is a Chicago hope hybrid tea rose and just keeps getting worse and worse. I believe it has blackspot, leaves get dark spots that get bigger until they cover whole leaf and gets on the leaves all around it if I don't clip them off as soon as I start seeing the spots. I am using a sulfur based spray on both plants every 7 days and feed it MG for roses (1gallon each plant) every 7 days. It starts to look better then bad again, it's done this all spring/summer. I've had a few blooms which are beautiful but it keeps getting to be less blooms and a lot smaller than when I first purchased it. It'll be winter soon and I'm wondering if there's a way to fix it that I'm not doing? Would it be better to leave the sickly rose in the ground and mulch or dig it up/pot it and bring inside for the winter? I'd appreciate any help I'd really like it to make it but there's only couple stems left alive on it and they are pretty short.
Black Spot: Rose plant leaves with black spots that eventually turn yellow have black spot. This is often caused by water splashing on leaves, especially in rainy weather. Leaves may require a protective fungicide coating, which would start in the summer before leaf spots started until first frost. Thoroughly clean up debris in the fall, and prune out all diseased canes.