sallyg said:Good luck!
Just sayin' .. I killed knock outs without using spray lol
gardenfish said:You know, I think I would start by cutting out the dead stuff. Then see what happens. The shrubs may look a little uneven at first, but they should put new growth out and it will much better with time. Knockouts are nearly indestructible, but then general rule of thumb for severely trimming all shrubs is only 1/3 of the foliage at a time. I have knockouts at a Master Gardener project of mine, and they got severe blackspot last year, something knockouts rarely have an issue with. I cut them back 2/3 with an electric hedge trimmer. This was in July. They survived and recovered nicely.
Not that I'm telling you to cut yours back by that much! Start slow. You can always cut more, but you can't put it back. I do see what looks like some blackspot. You might want to spray sometime down the road. Copper is good.