More pictures

How big is the container, gallon wise, that contains your Knock Out? You've had the Knock Outs two years now?

Mini roses get every insect and fungal disease that comes down the pike. What is your mini's varietal name? In what size container is it growing?

Moses

Some of these leaves look burnt and dry, fungicides and neem oil can cause this if applied incorrectly.

How is the drainage in your pots? If the soil isnt draining well that can cause problems as well. I second Moses and his question about pot size, it might be time to size up your pots.

I think pot size are ok for the plants, especially after I’ve pruned them smaller. I’ve replanted the year I got them into bigger pots they needed. Does container size impact resistance to black spot? Is that the main issue?

The roses are going down so quickly,
within days…went from a few leaves with a problem to the pictures above to now 90% of leaves having problems …. What am I doing wrong????

How do I apply fungicide correctly? I’ve been spraying those when I noticed the problem as often as I could. Was that supposed to be differently? I tried not to apply during mid day when in full sun, more afternoons and evenings

The problem is spreading… am I better off doing nothing? Not spraying? The mini rose seems to do better than all but it’s further away. I don’t know the variety (got it in a small pot at a store and replanted over the years info bigger ones) but now it’s also developing this problem….

Here are pictures of mini roses, leaves are starting to show same symptoms as the knockout roses…

For reference this was my knockout rose last May. How do I bring it back? Thanks!

It’s now in a bigger pot

What is the volume size, in gallons, of the pot you intend to grow the sick Knock Outs in now? The exact answer to my question is pivotal to further advice I can give.

As Heather pointed out, you have been OVER CURING with spraying to attempt to restore the bushes, when pot size is at the root of their problem.

Moses

I grow lots of roses in pots (currently over 100 while waiting on construction projects) and the key to keeping them healthy is pot size and regular feeding and watering. A knockout rose is normally able to fight off blackspot but when stressed by a small pot or lack of nutrients it will succumb.

I don’t spray but if I did I would follow the instructions on the bottle. The burnt leaves are a sign that you have been over spraying. I would stop spraying, hose down the plant to get rid of the neem oil and remove the worst of the burnt leaves. If you havent already, start a fertilizer program. I use fish emulaion for my pots but Osmocote is a great easy option, my dad uses it for his potted hybrid teas and they always look fabulous.

Stop spraying ! You're killing your roses by trying to cure them. Keep them watered, fed, and hope for the best.

To address a comment you made above, 1 must apply fungicides before problems. It prevents problems it does not cure them.