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Is it bad to cut back my Knockout Rose bushes in late summer? My rose bushes have not done well this year. They have grown well but not flowered as much as in year's past. I want to cut them back significantly to make them all look uniform in height but I don't want to kill them. Also the Japanese Beatles have been very bad and I want to know what I can spray on the bushes to get rid of them. Any ideas are welcome.

Thanks,

Just Getting Started

You can trim your Knockouts a little to shape them but I wouldn't cut them back severely this late; it's getting close enough to Fall, and first frost if you're Zone 5 or below, that you don't want to be stimulating much new tender growth that will use up the plant reserves and die with the first frost.

On the Japanese beetle side, I don't have them yet in Kansas so I'm afraid others would be a better resource. Good luck with them!

I agree...the best time to trim them back harshly would be next year right after the first flush of blooms. (Except for removing any dead canes in the spring)
As for the Japanese beetles, they are winding down at this time of year (I haven't seem any for a couple weeks here in MA, so you're probably just stuck with them for another week or two) If you can, just hold out till then, hand pick as many as you can, and do with them as you will (to keep them from becoming next year's beetles)