I have black spots on my rose bush leaves
I have rose bushes that are flowering but have black spots on the leaves.
Certified GKH Gardening Expert
That is likely what is known as Black Spot Fungus. Here is a link to an article I wrote about it for you: https://www.gardeningknowhow.com/ornamental/flowers/roses/black-spot-roses.htm
The Mancozeb product is available through http://www.rosemania.com as well as the Honor Guard product. Green Cure, an Earth Friendly fungicide, is available at a website called Planet Natural.