Knockout Rose Disease and Treatment
All of our knockout roses have become infected with some sort of disease that I cannot identify. Nearly all of the leaves have turned brown and are falling off. The roses bloomed, and the browning started soon after.
Several neighbors have the plants and I see no problems with theirs. we have plants in different parts of our yard and they all seem to be afflicted. Perhaps ours are a different type.
We would appreciate any advice on this issue. I'm considering either cutting them all the way back or just digging them up, but would love to save them if we can.
DeKalb County Georgia
This is not a disease it looks like sawfly damage which are insects. Primarily spring insects that feed on the undersides of leaves. Control them with an insecticide such as Sevin or Bayer Advanced. Then, re-fertilize and mulch and water well to push out new growth. Should recover just fine!
Thank you very much. I'll get on it right away.
Should I cut these back? The entire plants are pretty defoliated?
Can cut back some, like 3-4 inches to encourage new foliage and flower but not too hard! Keep watered and fertilized
Great, thanks again.