What is wrong with my knock out roses? (pic)
I planted 4 knock out roses from the farmers market in August of last year. This past spring, they looked great. I treated with Bayer 3-in-1, once in May, once in June. We sprayed with Sevin one time in June to prevent Japanese Beetle damage. I watered them regularly last year but not as much this year. We have had a good amount of rain this summer. All was well.
Since August, they have gone downhill. They have dropped a considerable amount of leaves. There is some new growth on them and they are flowering out, but they look bare. I have not fertilized since June.
I have 6 additional knock out roses in the yard that I planted two years ago. I bought these from a nursery. They got the same treatment as the farmers market roses. For some reason, they look great while the farmers market roses look bad.
There is no black spot or rust that I can see on the leaves. Does anyone have any ideas about what the problem is and if I can/should do anything to help it? Here's a photo -