Question
Charleston, SC - Zone 8. I just recently planted 9 knockout roses. They are blooming beautifully. A few have developed some yellowing leaves on the lower part of the plant with dark green spots. I am watering them about once a week. I did not notice this until after we received a lot of rain about 2 weeks ago. Can you tell me if this means they received too much water or is it a fungus? If so, how should I treat and should I remove the yellowing leaves?

Answer
Roses don't mind rain but they don't like a lot of it at one time. Everyone this year is having problems with the weird weather. The long time of rain is what caused your problem. I would just take the yellowed leaves off. Also, because of the large amount of rain, if your soil isn't a clay type, some of your fertilizer will probably be washed away. A handful sprinkled all around the base of the rose will certainly perk them up. Knock Out roses are tough so I wouldn't worry about them as they will bounce back when the sun shines. If you get another long spell of rain, then these symptoms will appear again. Hope this helps.