Need advice black spot on Knock out cane?

Hingham, MA

Hi.. I thought I was having problems with slugs from holes in leaves so starting using a neem treatment. As I went out to do a check on the bush, I realized I might have a larger problem? Is this Black spot on the canes? Is this something that means Yank by attaching to an SUV and don't look back or is it a harsh cut down now or in the fall? I appreciate any advice.

Thumbnail by Marmel41
Powder Springs, GA(Zone 7b)

I cut mine back hard usually twice a year. They do get some black spot on the leaves but not bad enough to spray. Anyway these are hard to kill. I dug up the 6 in the front yard and moved them to the back. The roots left behind sprouted some new shoots and I dug those up and kept in a garden cart full of rain water all winter and the ones that had roots in the water survived and I've planted most of those in other spots and pots. Now the original spot they were dug up from have sent up new roses and blooming once again. GRRR!

Anyway I trimmed mine to 12 to 18 inches high in spring and later in summer to rejuvenate and get rid of dead and weak stems.

Good luck!

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