I am getting black spots on my Knock Out roses. I didn't think this was supposed to happen. Please help.

Answer 1

Clip off and dispose of affected leaves. Prune an infected branch back to healthy, outward-facing bud. Pick up and destroy any leaves that fall to the ground. Spray with organic copper-sulfate fungicide or the botanical pesticide neem. Or use a synthetic fungicide registered for roses that contains the active ingredient captan or mancozeb. Follow label directions carefully.Water the plant in the morning so that leaves can dry complete by nightfall. Mulch with an organic material such as shredded bark, pine needles, or straw to prevent water splashing onto leaves.
Cause: Rose blackspot is a fungal disease that can infect almost any type of rose. It is a widespread problem in all but the most arid climates. Blackspot flurishes when temperatures range between 50 and 80F. As the fungi matures, they release thousands of microscopic spores, The spores germinate on new leaves that remain continuously damp for more than six hours.

Answer 2

Its a fungus. Roses are members of the cactus family so you need to remember that when watering, Dont get the leaves wet, dont water at night, dont overwater. Trickle water for about an hour in the morning once a week if its hot out.
Bury cornmeal around the base of the plant, for some reason this helps with black spot. Put it in the hole when you plant if you can.
Another thing that helps with roses, again I dont know why, is if you bury banana peels around the plant.

Answer 3

This is a fungus.If you run sprinklers at night,and water is left on the rose,if will cause a fungus.Adjust your sprinklers to water the ground or base,never water the rose.You can use any fungicide for roses by Ortho.They are very effective.