I would replace them. There are plenty of husky, reasonably priced Knock Outs in the nurseries. You will lose a lot of time babying those laggers. If they will even respond positively is questionable.

Moses

I have 3 knockouts that I bought from Lowe's, planted in February, then had 2-3 cycles of freezing and thawing quickly.

All 3 died back to the ground.

1 didn't make a comeback, the 2nd looks like yours here and has a single bloom already, while the 3rd is back to it's original size.

I bet it would take less than a month for it to regrow, but really it only depends on whether or not you need to save the $25.

I agree with Moses and JC. These are so cheap right now to replace especially since your'rs was small. And you can get a full healthy one and start over. I have a few and there was alot of dieback this year but mine are more established then yours so they're fine.

I'll take a different viewpoint (agreeing with JC) and suggest that in cold zones, this can be all that you get of winter survival from Knockouts. I prune about 50 Knockouts at my church every year and this is what they usually look like before I get to them. As long as they have a good root system, they're usually back to full bushes and blooming along with every other Knockout in time.

They bill Knockouts as "trouble free" but neglect to inform those of us in cold zones how much pruning they'll need in spring to cut out the dead wood. Looks totally normal for Knockouts in my experience.

Cynthia

Nippstress -

That’s just it - they do not yet have a good root system since they were transplanted in March. Does this vary your thinking at all?

I don't think the transplanting would affect their root system, since they set down roots last year and you moved them when dormant. I'd presume that the roots are fine but that the dead canes are most decidedly dead. Just prune out the dead ones and enjoy the growth of the remainder. My expectation is that this rose will catch up to new ones in no time.
Cynthia

Whether you replace or not, try either of these two methods as winter sets in next year.

Method 1} Drive four stakes into the ground to form a box around the rose. Wrap the outside of this box with burlap. Run over tree leaves with a bagging mower and fill the inside of the burlap by packing the leave waste to cover the rose bush to a height of about a foot. Add water and place a wire mesh over the top to prevent the wind from blowing the leave mulch out.

Method 2) Cover the base of the rose bush with a mound of compost to about 8 inches and leave until late March. Scratch the compost into the soil and be prepared to prune.

Both of these methods will result in more of the cane staying green for several more inches above the ground.

All great suggestions. I pruned the dead stuff away and will likely give them a few weeks to a month before coming to a decision on how to proceed.

I swear I just posted this, but now I’m not seeing it. Do these pics taken 6 days later influence your decision either way? There is definitely life. Decent size blooms, tiny plants

I’m greedy. I had some die back to the ground because I planted too early this year.

They looked like yours but I just added replacements instead of actually replacing them.

You definitely have surviving roses and they'll improve with the year, but you're right that these are tiny right now. Take it as a survival instinct that the Knockouts will bloom when this tiny and that's part of why they get recommended a lot. Since you've also demonstrated to yourself that Knockouts have some substantial dieback in your zone, I'd recommend a version of what JC describes and intersperse these with another rose that's likely to do better in your zone. Most of the Easy Elegance roses are available locally and do fabulously for me over the winter. The Canadian roses will have no dieback but might dwarf these Knockouts. There are dozens of roses that will probably be more reliable for you, so it's a question of what you prefer.

My recommendation is to watch this year and see if their recovery is acceptable to you and if not take them out in August or September. In the meantime, you can ask about other more robust varieties to space in between them or replace them, whichever you choose.

Cynthia

The knockouts definitely do well here. The are my other two and have been in the ground for about a season and a half.