Same problem.

Asked June 12, 2019, 11:09 AM EDT

I have the same problem with my knockout rose bush. Can I cut it back?

Suffolk County New York roses

4 Responses

Thank you for your question. Since the Extension system often receives over 200 questions each month about Knock Out roses, we don't know which prior problem you are referring to. Could you please send a photo of the plant and the parts you are inquiring about? Thank you!

My knockout rose bush bloomed and then the leaves turned brown. There are no other buds. Should I cut it back?

My knockout rose bush bloomed and then the leaves turned brown. There are no other buds. Should I cut it back?

Thank you for the photos. Your plant appears to be infested with at least one type of insect, and just cutting the foliage back will not control the insect. I suggest you contact your county Extension office (http://ccesuffolk.org/) and ask where you can take your plant and some leaf samples to the office to be examined. There may well be some nutritional deficiencies as well, but the skeletonized leaves mean those described here:

"Aphids—Reduced shoot growth, distorted or pale foliage, small insects clustered on stems and shoots Many natural enemies exist. Ladybugs and syrphid fly larvae eat many aphids. A strong jet of water can be used to wash aphids from plant surface or spray with insecticidal soap. If a pesticide is necessary consult Pest Management Around the Home. A multipurpose rose spray may be purchased.

Japanese Beetle, Rose Chafer—Leaves skeletonized, flowers eaten Hand pick adult beetles and drop in a jar of soapy water. Individual flowers for show can be protected with covers (bags). If a pesticide is necessary consult Pest Management Around the Home.

Roseslug and other sawfly larvae—Upper leaf surfaces skeletonized, leaves devoured, only midvein remains. If the infestation is small, remove affected leaves. Handpick larger larvae. If a pesticide is necessary consult Pest Management Around the Home. Rose midge—Buds or shoots blacken or die. Remove and destroy (bury, burn, or put in the trash) all affected buds and shoots as soon as you spot them. If a pesticide is necessary consult Pest Management Around the Home." http://cceoneida.com/resources/ipm-integrated-pest-management-of-roses

In order to treat effectively, the correct insect needs to be identified. Good luck!